嵌入式学习-复习-面试笔试答案

一：Linux系统基 常用的linux命令，并说明其功 二：C语言基 C选择题- C简答题- C编程题- C++选择题- C++填空题- C++简答题- C++编程题- 五：UC环境编 UC选择题- UC简答题- 六：VC环境编 VC选择题- VC简答题- 七：数据 一：Linux系统基linux -apwd查看当 datecatshutdown/init0init6/rebootcdls查看 mkdirrm删 mvln创建软连接(ln–stouch find/-namefile1从 o．which显示一个二进制文件的完整路径p．groupadd创建一个新用户组q．useradd创建一个新用户r．tar包操作命令s．zip压缩命令t．unzip解压命令u．rpm安装/rpm二：C语言基C选择题-一个C程序的执行是 mainmainC.main函数开始，到本程序文件的最后一个函数结束D.main函数结束C程序中，mainCCC程序进行编译的过程中，可发现注释中的拼写错误C一个可编译为可执行程序的CmainCC程序中，注释说明只能位于一条语句的后面int7A.(x=y=6,x+y,x+1)B.(x=6,++x,x)C.(x=6,D.(y=6,y+1,x=y,正确答案设有说明：charwintxfloaty;doublez;w*x+z-y正确答案 正确答案x、y、zintx=(y=(z=10)+5)-5x、y、z正确答案intmainvoidinta=printf("%d",a+++++a);return0;}正确答案intmainvoidintx;floatprintf("Enterxandy:return0;}Enterxandy:2scanf("%d%f",x,y);printf("x+y=%4.2f",scanf("%d%f",x,y);printf("x+y=%3.2f",scanf("%d%3.1f",&x,&y);printf("x+y=%4.2f",scanf("%d%f",&x,&y);printf("x+y=%4.2f",正确答案 正确答案00正确答案intmainvoidinta,b,a=b=c=++a||--b&&printf("%d,%d,%d",a,b,c);return0;正确答案分段函数y=f(x)的值表如下所示： < x–= > x+A.y=x+if(x>=if(x==

y=y=x-B.y=x-if(x!=if(x>y=x+y=C.if(x<=if(x<y=x-1;y=y=x+D.y=if(x<=if(x<y=x-y=x+正确答案intmainvoidinta=10,b=9,c=(--a==b++)?--a:printf("%d,%d,%d",a,b,c);return0;}正确答案intmainvoidinti,for(i=1;i<=100;{x=if(++x%2==if(++x%3==if(++x%7==printf("%d",}return} 正确答案for(i=100;i<=200;i++){if(!(i%printf("%d\n",i);}for(i=100;(i%3)&&i<=200;i++)printf("%d\n",i);for(i=100;(i%3)||i<=200;i++)printf("%d\n",i);for(i=100;i<=200;if(i%printf("%d\n",i);D.for(i=100;i<=200;i++)if(i%printf("%d\n",正确答案

intmain(void)inta,b,c,d;scanf("%d",&a);for(b=3;b<=a/2;b+=2){for(c=2;c<=sqrt(b);c++)if(b%c==0)if(c<=sqrt(b)) d= for(c=2;c<=sqrt(d);c++)if(d%c==0)if(c<=sqrt(d))printf("%d=%d+%d\n",a,b,}return}A.a+ B.a– C.a* D.a/正确答案intmainvoidintk=0;charc='A';do{switch(c++)case'A':k++;casecasek+=casek%=casek*=k/=}while(c<printf("k=%d\n",k);return0;}第一次循环后：C=‘BK=2C=‘C第三次循环后：C=‘D’K=1;第四次循环后:C='E',10;第五次循环后：C='F'K=4A.k= B.k= C.k= D.k=正确答案正确答案inta[2][3]=inta[][3]=inta[2][3]=inta[][3]=正确答案intmainvoidinta[6][6],i,for(i=1;i<6;for(j=1;j<6;a[i][j]=(i/j)*(j/i);for(i=1;i<6;i++){for(j=1;j<6;printf("%d",a[i][j]);printf("\n");}return}1111111111111111111111100000100000100000100000C.00001000100010001000100000010101000100010101000正确答案C语言函数参数的说法中正确的是B.实参和与其对应的形参共享同一个单元正确答案voidhanoiintncharfromcharbychartoif(n)hanoi(n-1,from,to,by);printf("%c->%c\n",from,to);hanoi(n-1,by,from,}}intmain(void)hanoi(3,'A','B',return}mainhanoiA.A->CA->BC->B->C->BA->CA->B.A->CA->BC->A->B->CA->CA->C.A->CA->BC->A->B->AB->CA->D.A->CA->BC->A->B->AB->CA->正确答案正确答案 #defineXa%4#defineYX+3#defineZY*X/2intmainvoidinta=printf("%d",++Z);return0;} 正确答案#defineSQUARE(x)#defineSQUARE(x)正确答案char*s="abcde";s+=printf("%d",s);C.字符cintmainvoidinta[]={10,20,30,40,printf("%d\n",*((int*)(&a+1)-1));return0;} A.a+B.a+C.*(a+正确答案qsortintcompare_cstr(constvoid*pv1,constvoid*pv2){return① }intmain(void)constchar*cities[]={qsort size_tfor(i=0;i<sizeof(cities)/sizeof(cities[0]);i++)printf("%s\n",cities[i]);return}strcmp(*(constchar**)pv1,*(conststrcmp(*(constchar*)pv1,*(conststrcmp(*pv1,strcmp(pv1,正确答案B.cities,sizeof(cities)/sizeof(cities[0]),C.cities,sizeof(cities)/sizeof(cities[0]),sizeof(cities[0]),compare_cstrD.cities,sizeof(cities)/sizeof(cities[0]),sizeof(cities[0])正确答案typedefvoid*(*square_t)(int*x);void*square(int*x)*x*=return}intmain(void){intx=2;((square_t)((square_t)((square_t)square(&x))(&x))(&x))(&x);printf("%d",x);return} 正确答案intmain(void){intna=1;intnb=swap(&na,&nb,sizeof(na));printf("%d,%d\n",na,nb);doublefa=0.1;doublefb=swap(&fa,&fb,sizeof(fa));printf("%g,%g\n",fa,fb);char*sa="o";char*sb=swap(&sa,&sb,sizeof(sa));printf("%s,%s\n",sa,sb);return0;}2,0.2,world,swap函数应定义 voidswap(int*a,int*b,size_tsize){intc=*a;*a=*b=}voidswap(double*a,double*b,size_tsize){doublec=*a;*a=*b=}voidswap(char**a,char**b,size_tsize){char*c=*a;*a=*b=}voidswap(void*a,void*b,size_tsize){void*c=malloc(size);memcpy(c,a,size);memcpy(a,b,size);memcpy(b,c,size);free(c);}正确答案 charsz[5]={'a','b',0,'c','\0'};printf("%s",sz);D.abc正确答案abchara[]=charb[]={'A','B','C','D','E',A.abB.abC.abD.ab数组长 chara[]="abcdef";charb[]="ABC";memcpy(a,b,strlen(b)*sizeof(b[0]));printf("%s\n",a);strcpy(a,b);printf("%s\n",a);正确答案chara[3bTARENAab;printfsa);正确答案下面的代码意在实现一个将字符串转换成浮点数的函数（Catof函数。doublemy_atof(constchar*a){doublef=0;if )for(;isdigit(*a);a++)f=f*10+(*a-'0');if(*a=='.'){size_tdec=0;for ;isdigit(*a);a++)f=f*10+(*a-'0');}for(;dec; f/=}}return}A.strlen B.strlen(a)&& C.a&&strlen D.a||strlen正确答案 D.a=正确答案 D.dec>正确答案structStudent{charname[20];boolsex;intage;structintyear;intmonth;intday;}structStudentA.year=month=day=student.month=student.day=C.birth.year=birth.month=birth.day=student.birth.month=student.birth.day=正确答案正确答案32IBM-PCCstructAchar shortint}则变量a所占用的字节数和成员布局 正确答案intmainvoidunionchars[5];intn;}sprintf(u.s,printf("%#x",u.n);return0;} 正确答案inta=10,b=20;a^=b^=a;a^=ab 正确答案fopen函数打开一个新的二进制文件，该文件要既能读也能写，则文件打开方式 正确答案返回实际的字节数，出错返回返回实际的字节数，若出错或遇到文件尾，该值将小于所期望的字节数fseekfp20L2)20个字节intmain(intargc,char*argv[]){if(argc<3)printf("Usage:%s<source_file><dest_file>\n",argv[0]);return-1;}FILE*src=① if(!src){printf("Unabletoopensourcefile\n");return-1;}FILE*dst=② if(!dst){printf("Unabletoopendestfile\n");return-1;}intunsignedcharbuf[1024];while(③ if )printf("Unabletowritedestfile\n");return-1;}if )printf("Unabletoreadsourcefile\n");return-1;}fclose(dst);fclose(src);return0;}fopen(argv[0],fopen(argv[1],fopen(argv[2],fopen(argv[1],正确答案fopen(argv[0],fopen(argv[1],fopen(argv[2],fopen(argv[2],正确答案A.bytesfreadbuf1sizeofbufsrc)B.(bytes=fread(buf,1,sizeof(buf),src))==sizeofC.bytes=fread(buf,sizeof(buf),1,D.fread(buf,1,sizeof(buf),正确答案fwrite(buf,1,sizeof(buf),dst)!=sizeoffwrite(buf,1,bytes,dst)<=fwrite(buf,1,bytes,dst)!=fwrite(buf,bytes,1,dst)!=正确答案feoffeof正确答案my_printf（Cprintf的简化版本itoa用于将整数按十进制转换为字符串。请将其中缺失的部分补全。char*itoa(inti,char*a){if(a){size_tfor(n=0;i;i/= if(!a[n++]=a[n]=size_tlen=strlenfor(n=0;n< ;n++)charc=a[n];a[n]=a[len-1-n];a[len-1-n]=}}return}intmy_printf(constchar*format,...){intcn=0;va_list charfor(c=*format;c;c=*(++format))if(c=='%')switch(c=*(++format)){case'd':{intn=va_arg(ap,int);charsz[128];itoa(n,fputs(sz,stdout);cn+=strlen(sz);}case'c':charc=va_arg(ap,int);putchar(c);}case's':char*psz=④ fputs(psz,stdout);cn+=strlen(psz);}}elseputchar(c);} return}intmain(void)my_printf("Integer:%d,Char:%c,String:%s\n", 2012,'C',"oworld");return0;}A.a[++n]=i%10B.a[n++]=i%10C.a[++n]=i%10+'0'D.a[n++]=i%10+正确答案A.len/ C.len/2– D.len-正确答案va_start(ap,正确答案va_arg(ap,va_arg(ap,va_arg(ap,va_arg(ap,正确答案va_endva_end(ap,va_end正确答案C简答题-intptr=(int*ptr=Amoreobscureapproach*(int*const)(0x67a9)=#includestdio.h"#defineSQR(X)intmain(intargc,char*{inta=10;intk=2;intm=1;a/=SQR(k+m)/SQR(k+m);return}defineX*Xa/==>a/==>a==>a=constconstcharcharconstchar*constconstconstconst位于星号的右侧，const就是修饰指针本身，即指针本身是常量。constcharcharconst对象指针，p不是常量,pconstchar*p;charc1='a';charc2='b';char*const此时*ppconstchar*constvoidDoSomeThing(char*p){charstr[16];intn;assert(NULL!=p);判断sscanf(ps%dstrn);if(0==strcmp(str,{}}答案 sscanf(ps%dstrVoidtest1(){charchar*str1=" strcpy(string,str1);}Voidtest2(){charstring[10],str1[10];for(i=0;i<10;i++){str1[i]}}数组越界，strcpy要判断’\0’才结束Voidtest3(char*str1){char{}}====strcpy拷贝的结束标志是查找字符串中的\0因此如果字符串中没有遇到\0制，直到遇到\0,建议使用strncpy和memcpy{//charstr[]="world";cout<<sizeof(str)<<":";char*p =str; cout<<sizeof(p)<<":";chari =10; cout<<sizeof(i)<<":";void*p =malloc(10);cout<<sizeof(p)<<endl;}{//unionV{structX{unsignedchars1:2;unsignedchars2:3;unsignedchar}unsignedchar}v.c=} #include<stdio.h>inta[int*p[]={a,a+1,a+2,a+3,a+4};voidmain(){}9584structA{chart:4;charunsignedshorti:8;unsignedlongm;}sizeof(A)=7（不考虑边界对齐）--m放在结构体最开始，那么=16struct //DeclareCELLbit{unsignedcharacter:8;// unsignedforeground:3;//00000???unsignedintensity:1;//unsignedbackground:3;//0???0000unsignedblink :1;//?} //Arrayofbitintadd_n(intn){staticinti=100100return}答:因为statici的值会保留上次的值。去掉static#defineswap(x,y)\(x)=(x)+(y)=(x)–(x)=(x)–14．i最后等于多少?inti=1;intj=if((i>j++)&&(i++==j))答:i5unsignedshortinti=*(array+i)=答（试编写函数判断计算机是大端还是小端大端是低地址存，小端是低地（答bool{unsignedshortusData=unsignedchar*pucData=(unsignedchar*)&usData;return(*pucData==0x22);}voidGetMemory(char*p){p=(char*)malloc(100);}voidTest(void){char*str=NULL;} oworld");将使程序:charchar*p=(char*)malloc(100);returnp;}voidTest(void){char*str=NULL;}方法二:voidGetMemory2(char**p)变为二级指针.voidGetMemory2(char**p,intnum){*p=(char*)malloc(sizeof(char)*}static变量和static函数各有什么特点？static变量：在程序运行期内一直有效，如果定义在函数外，则在编译单元内可见，如果在函数内，在定义的函数块内可见；static函数：在编译单元内可见；voidFunc(char{}答:4分析:＃include<stdio.h>{inti;charx[2];void{a.x[0]=a.x[1]=}答案：266(低位低地址，高地址，内存占用情况是Ox010A）{union*定义一个联合*/inti;struct*在联合中定义一个结构*/charfirst;charnumber.half.first='a';/*联合中结构成员赋值*/}答案：AB(0x41对应'A',是低位；Ox42对应'B',是unsignedlongval;chara=0x96;charb=0x81;val=b<<8|a;问val= char默认为无符号还是有符号。unsignedchar22．.hifndef/define/endif的作用？答：防止该头文件被重复（。＃include<file.h>includefile.h"答：前者是从StandardLibrary的路径寻找和file.h，而后者是先从当前工作路径搜寻并file.h（。const与#define相比，有何优点？const常量有数据类型，而宏常量没有数据类型。编译器可以对前者进行类型安全constx2inti=cout<<boolalpha<<((i&(i-1))?false:true)<<，chara[]=“a[0]=char*p=“world”;//pp[0]=‘X’;//sizeof可以计算出数组的容量（字节数。sizeof(p),p为指针得到的是一个指针pC++/C语言没有办法知道指针所指的内存容量，chara[]="oworld";char*p=a;coutsizeof(a)endl12字节cout<<sizeof(p)<<endl;//4字节voidFunc(char{coutsizeof(a)endl4100}cout<<FILE cout<<LINE FILE和LINE是系统预定义宏，这种宏并不是在某个文件中定义的，而是由编译器定main答案：可以，可以用_onexit一个函数，它会在main之后执行intfn1(void),fn2(void),fn3(void),fn4(void);voidmain(void{String_onexit(fn1_onexit(fn2_onexit(fn3_onexit(fn4printf("Thisisexecutedfirst.\n"}int{printf("next.\n");return0;}int{printf("executed");return0;}int{printf("is");return0;}int{printf("This");return0;}The_onexitfunctionispassedtheaddressofafunction(func)tobecalledwhentheprogramterminatesnormally.Successivecallsto_onexitcreatearegisteroffunctionsthatareexecutedinLIFO(last-in-first-out)order.Thefunctionspassedto_onexitcannottake结构和联合都是由多个不同的数据类型成员组成,但在任何同一时刻,联合中只存放了一个被选中的成员（所有成员共用一块地址空间）而结构的所有成员都存在（不同成对于联合的不同成员赋值,将会对其它成员重写,原来成员的值就不存在了,而对Newdeletemallocfree的联系与区别且不能初始化对象，new会自动调用对象的构造函数。deletedestructor，而freedestructor.#defineDOUBLE(x)i5*DOUBLE(5)i是多少？答案：i30。BOOL,int,float,a与“零”的比较语句BOOL: if(!a)orif(a)int: if(a==0)float: constEXPRESSIONEXP=0.000001if(a<EXP&&a>-EXP)pointer:if(a!=NULL)orif(a==C编译程序还是由C++编译程序编译的？#ifdefcplusplus用预处理指令#define一个常数，用以表明1年中有多少秒（忽略闰年问题#defineSECONDS_PER_YEAR(60*60*24*MIN，这个宏输入两个参数并返回较小的一个。#defineMIN(A,B)((A)<=(B)?(A):(B))a一个整型数（An一个指向整型数的指针（Apointertoan一个指向指针的的指针，它指向的指针是指向一个整型数（Apointertoapointertoan10个整型数的数组（Anarrayof1010（Anarrayof10pointersto10个整型数数组的指针（Apointertoanarrayof10一个指向函数的指针，该函数有一个整型参数并返回一个整型数（Apointertoafunctionthattakesanintegerasanargumentandreturnsaninteger）10个指针的数组，该指针指向一个函数，该函数有一个整型参数并返回一个整型数（Anarrayoftenpointerstofunctionsthattakeanintegerargumentandreturnaninteger）inta;//Anint*a;//Apointertoanint**a;//Apointertoapointertoaninta[10];//Anarrayof10int*a[10];//Anarrayof10pointerstoint(*a)[10];//Apointertoanarrayof10int(*a)(int);//Apointertoafunctionathattakesanintegerargumentandreturnsanint(*a[10])(int);//Anarrayof10pointerstofunctionsthattakeanintegerargumentandreturnanintegerC编写死循环呢？while(1){for(;;){在模块内（但在函数体外，一个被为静态的变量可以被模块内所用函数，但 函数被限制在它的模块的本地范围内使用。大多数应试者能正确回答第一部分，一部constconstDanSaksconstESP(译者：EmbeddedSystemsProgramming)const能做什么和不能做什么.如果你从没有读到那篇文章，只要能说出const意味着“只读”就可以了。尽管这个答案不constinta;intconsta;constint*a;int*constintconst*a就是，整型数是不可修改的，但指针可以a是一个指向整型数的常指针（也就是说，指针指向的整型数是可以修改的，但指针是不可修改的a是一什么还要如此看重关键字const呢？我也如下的几下理由：关键字const的作用是为给读你代码的人传达非常有用的信息，实际上，一个参数你就会很快学会感谢这点多余的信息（当然，懂得用const的程序员很少会留下的让const可以使编译器很自然地保护那些不希望被改变的参数，防止其bug的出现。inta=5,b=7,c;c=a+++b;c=a+++因此,a6b7c12{char*p1=“name”;char*p2;memset(p2,0,20);while(*p2++=*p1++);}答案：:empty{intx=20,y=35;x=y+++x++;y=++y+++x;}答案:{int}答案#defineswap(a,b)a=a+b;b=a-b;a=a-b;Intswap2(inta,intb);void{intx=5,y=10;swap(x,y);}intswap2(inta,int{inttemp;return}答案1010,{char*ptr=”Cisco}答案:iscoSystemsscosystems{chars1[]=“Cisco”;chars2[]=“systems”;}Answer:{char*p1;charp1=(char*)malloc(25);p2=(char*)malloc(25);}答案intx;int{}intchangevalue(int{}void{intx=10;printf("Firstoutput:%dn",x);printf("Secondoutput:%dn",x);}答案:1213{intx=10,y=15;x=x++;y=}Answer:11,{inta=0;printf(“CiscoSystems\n”);printf(“Cisco}答案TwolineswithCiscoSystemswillbecharstr1[]="abc";charstr2[]=constcharstr3[]="abc";constcharstr4[]="abc";constchar*str5="abc";constchar*str6="abc";coutboolalphastr1==str2endl;//输出什么？coutboolalphastr3==str4endl;//输出什么？coutboolalphastr5==str6endl;//voidUpperCase(charstr[])//str{for(size_ti=0;i<sizeof(str)/sizeof(str[0]);++i)if('a'<=str[i]&&str[i]<='z')str[i]-=('a'-'A'}charstr[]=coutstr字符长度为sizeof(str)/sizeof(str[0endl;UpperCase(str);cout<<str<<voidchar2Hexcharc)//16{charch=c/0x10+'0';if(ch>'9')ch+=('A'-'9'-charcl=c%0x10+'0';if(cl>'9')cl+=('A'-'9'-1);cout<<ch<<cl<<'';}charstrIlove中国for(size_ti=0;i<strlen(str);++i)char2Hex(str[i]);cout<<void*mymemcpy(void*dest,constvoid*src,size_tcount{char*pdest=static_cast<char*>(destconstchar*psrc=static_cast<constchar*>(srcifpdest>psrc&&pdest<psrc+count){for(size_ti=count-1;i!=-1;--i)pdest[i]=psrc[i];}{for(size_ti=0;i<count;++i)pdest[i]=psrc[i];}return}intmain(void{charstr[]=" mymemcpy(str+1,str+0,9);cout<<str<<endl;system("Pause");return0;}求下面函数的返回值（int{intcountx=0;{countx++;x=x&(x-1);}return}C编程题-C写一个输入的整数,倒着输出整数的函数,答voidfun(inta{printf("%d",a%10);a/=10;if(a<=0)return;fun(a);}strcpy的函数原型：char*strcpy(char*strDestconstchar*strSrc)strDest是目的字符串，strSrcC++/C的字符串库函数，请编写函数strcpy。char*strcpy(char*strDest,constchar{if(strDest==NULL||strSrc==NULL)returnNULL;if(strDest==strSrc)returnstrDest;char*tempptr=strDestwhile((*strDest++=*strSrc++)!=;returntempptr},第一大的数为constintMINNUMBER=-32767intfind_sec_max(intdata[],int{intmaxnumber=data[0];intsec_max=MINNUMBER;for(inti=1;i<count;i++){if(data[i]>maxnumber{sec_max=maxnumber;maxnumber=data[i];}{if(data[i]>sec_max)sec_max=data[i];}}returnsec_max}nodecharval;node*next;}boolcheck(constnode*headreturnfalse:无环；true:有环，一种O（n）的办法就是（搞两个指针，一个每次递增一步，一个每次递增两步，如果有环：boolcheck(constnode*{ returnnode*low=head,*fast=head->next;while(fast!=NULL&&fast->next!=NULL){}return}一个学生的信息是：，学号，，等信息，用一个链表，把这些学生信息连在一起，给出一个age,在些链表中删除学生等于age的学生信息。＃include＃include"conio.h"structstu{charname[20];charsex;intno;intstructstu*structstu*creatlist(int{int//h为头结点，p为前一结点，sstructstuh=(structstu*)malloc(sizeof(structstu));h->next=NULL;{s=(structstu*)malloc(sizeof(structstu));p->next=s;printf("Pleaseinputtheinformationofthestudent:namesexnoage\n");scanf("%s%c%d%d",s->name,&s->sex,&s->no,&s->age);s->next=NULL;p=s;}}voiddeleist(structstu*s,int{structstu*p;{p=s=s-printf("Therecordisnotexist.");{p->next=s->next;printf("Deletesuccessful!");}}voiddisplay(structstu{s=s->next;{printf("%s%c%d%d\n",s->name,s->sex,s->no,s->age);s=s->next;}}int{structstu*s;intn,age;printf("Pleaseinputthelengthofseqlist:\n");s=creatlist(n);printf("Pleaseinputtheage:\n");return0;}＃include＃includevoiduppers(char*s,char{{*us=*s-32;*us=}*us=}int{char*s,*us;charprintf("Pleaseinputastring:\n");s=ss;printf("Theresultis:\n%s\n",us);}#include<stdio.h>voidmain(){inti=60;intj=50;}//a=a+b-unsignedintintvert(unsignedintx,intp,intn)x的进行转换,p为起始转化位,nunsignedintintvert(unsignedintx,intp,intn){unsignedint_t=0;unsignedint_a=1;for(inti=0;i<n;++i){_t|=_a=_a<<}_t=_t<<p;x^=_t;returnx;}字.o（N）函数原型：intdo_dup(inta[],int三：C++基usingnamespacestd;classB{virtualvoidclassD:publicB{voidfun1(B*ptr){ptr->show();}voidfun2(B&ref){ref.show();}voidfun3(Db){b.show();}intBb,*p=newDfun1(p);//Dfun2(b);fun3(d);//B—虽然实参是子类对象，但是fun3的参数是基类对象， return} usingnamespacestd;classC1{classC2:publicC1{intC2cb2;C1*cb1;return} B. C. D. usingnamespacestd;intmain(){char*a[]={"o","the","word"};a+char**p=a;return0;} B. C. D.usingnamespacestd;classP{

charP(char*name="未知名称"){}"classB:publicP{B(char*"voidshowP(P}intBbook("人生");return0;}运行时的输出结果是书：人 usingnamespacestd;classBASE{char

BASE(charn):c(n){}virtual~BASE(){cout<<c;}classDERIVED:publicBASE{charc;

DERIVED(charintDERIVEDreturn}XYusingnamespacestd;classXCF{

int1：XCF(intaa=0):a(aa){cout<<"1";}2：XCF(XCF&x){a=x.a;cout<<"2";}intGeta(){returna;}intXCF*pd=newXCF(8);1deletepd;return0;}运行时的输出结果是Aab同时为正或同时为负的逻辑表达式是(D。D、class{virtualvoidfunc1()；voidfunc2();}ClassB:class{voidfunc1(){cout<<"fun1inclassB"<<endl;}virtualvoidfunc2(){cout<<"fun2inclassB"<<endl;}}A,Afunc1Bfunc2都是虚函数.BAfunc1Bfunc2都不是虚函数.CAfunc2是虚函数.，Bfunc1不是虚函数.D,Afunc2不是虚函数，Bfunc1是虚函数.（A,B,D三目运算符“以下有关C++C相对于C中整数类型的枚举，C++CC++可以，只要它们能构成重载且无歧CC++则是动态类型语言，但它们都属于强类型语言namespacens1{voidfoo(intn){cout<<"ns1:"<<n<<}}namespacens2voidfoo(doubled)cout<<"ns2:"<<d<<}}intmain(void){intn=10;doubled=1.23;usingnamespacens1;usingnamespacens2;foo(n);foousingns1::foo;foo(n);foousingns2::foo;foo(n);foo(d);return0;}ns1:ns2:ns1:ns2:ns1:ns2:ns1:ns2:ns1:ns1:ns1:ns2:ns1:ns2:ns1:ns1:ns2:ns2:ns2:ns2:ns1:ns1:ns2:ns2:正确答案intfoo(intn=10)return doublefoo(intn,doubled=1.23)return intmain(void)intdoublen=foon=food=food=foo(10,return15 行 正确答案以下有关指针和两种数据类型的比较，不正确的说法与指针的指针和指针数组不同，的和数组，甚至的指针都是不合与空指针和void型指针一样，也可以空和void型与向数组指针一，也可指数组的，但后保留了组的尺信息与指向函数的指针一样，也可以指向函数的，但对后者的解将导致其被隐正确答案在以下有关C++classUser{User(void):m_age(0),m_sex(true){}User(conststring&name,intage=0)m_name(name),m_age(age),m_sex(true){}User(conststring&name,intage,boolsex):m_name(name),m_age(age),m_sex(sex){}User(constUser&user)stringm_name;intm_age;boolm_sex 可以成功创建user对象UseruserUseruserUseruser=User("zhangtao",Useruser("liufei",28,正确答案下面的代码意在实现一个字符串类String，其内部需要动态一个内存缓冲区，以容classString{String(constchar*psz=NULL):m_psz ①)~String(void) String(constString&that):m_psz( ③)){}String&operator=(constString&rhs){ char*m_psz;};strcpy(newchar[strlen(psz?psz:"")+1],psz?psz:newchar[strlen(psz?psz:"")+strcpy(m_psz,psz?psz:psz?psz:正确答案A.m_psz=B.deleteC.deletem_psz正确答案A.that.m_pszthat.m_pszB.strcpy(m_psz,that.m_psz?that.m_psz:C.newchar[strlen(that.m_psz?that.m_psz:"")+D.strcpy(newchar[strlen(that.m_psz?that.m_psz:"")+1],that.m_psz?that.m_psz:"")正确答案A.m_pszrhs.m_psz;return*this;B.if(&rhs!=this)char*psz=newchar[strlen(rhs.m_psz)+1];delete[]m_psz;m_psz=strcpy(psz,}returnC.strcpy(m_psz,rhs.m_psz);returnD.char*psz=newchar[strlen(rhs.m_psz)+1];delete[]m_psz;m_psz=strcpy(psz,rhs.m_psz);return*this;正确答案下面的代码意在模拟一个银行的过程。Account类（代表账户）内部一个指向Bank类（代表银行）m_bank。AccountBank类的alloc接口，获取并初始化账号m_num。Bank类内部一个账户计数器m_accs，并alloc执行期间对该计数器累加，以确保账号唯一。classBankBank(void):m_accs(1000)intalloc(void)return}int classAccountAccount(void):m_num(m_bank->alloc())voidprint(void)cout<<m_num<< intstaticBank* AccountBank*Account::m_bank=newintmain(void)Accountacc_1,acc_2,acc_1.printacc_2.printacc_3.printg_acc.printreturn} 行，应按②修改，修改后运行，输出为③ 正确答案2112行修改为：Accountvoidm_banknewBankm_numm_bankalloc()){}2118行修改为：staticBank*m_banknew17182021行的顺序正确答案classclassNotify{Notify(Target*target,bool(Target::*callback)(int)):m_target(target),m_callback(callback){}boolrelease(intevent)①}②classTarget{Target(void):m_notify(newNotify ③ ④))~Target(void){deletem_notify;}Notify*getNotify(void){returnm_notify;}boolonNotify(intevent){cout<<event<<endl;…return}Notify*m_notify;};classSource{public:Source(void):m_notify(NULL){}voidsetNotify(Notify*notify){m_notify=notify;}voidrun(void)…m_notify->release…m_notify->release…}Notify*m_notify;};intmain(void){Targettarget;Sourcesource.setNotify(target.getNotify());source.run();return}returnm_callbackreturn(m_target->*m_callback)return(m_target->m_callback)正确答案bool(*m_callback)正确答案A.newTarget正确答案正确答案以下运算符 classInteger{Integer(intdata=0):m_data(data){}Integeroperator+(constInteger&i)const{returnInteger(m_data+}Integeroperator-(void)const{returnInteger(-m_data);}Integer&operator+=(constInteger&i){m_data+=i.m_data;return}Integer&operator++(int){return}int… 正确答案下面的代码意在实现一个可某种类型数据元素的数组容器。请将其中缺失的部分补typedef…TYPE;#defineSIZE256classArray{ operator[](size_ti){returnm_data[i];} operator[](size_ti)const{returnm_data[i];}TYPE…B.constTYPE正确答案B.constTYPE正确答案RGBm_r、m_g、m_b三个0~255范围内的整COLORREFColorRGB类型之间提供隐式转换的方法，以方便使用。请将typedefunsignedintCOLORREF;classColorRGB{ColorRGB(unsignedcharr,unsignedcharg,unsignedcharb):m_r(r),m_g(g),m_b(b){}ColorRGB(COLORREFcr) ②}unsignedcharm_r,m_g,…m_b(cr),m_g(cr>>8),m_r(cr>>m_r(cr),m_g(cr>>8),m_b(cr>>m_b(cr),m_g(cr<<8),m_r(cr<<m_r(cr),m_g(cr<<8),m_b(cr<<正确答案return(((((COLORREF)m_b)<<8)+m_g)<<8)+return(((((COLORREF)m_r)<<8)+m_g)<<8)+return(((((COLORREF)m_b)>>8)+m_g)>>8)+return(((((COLORREF)m_r)>>8)+m_g)>>8)+正确答案typedef…classSmartPointer{explicitSmartPointer(TYPE*p=NULL):m_p(p)~SmartPointer(void){if(m_p)}SmartPointer(SmartPointer&that):m_p(that.release()){}SmartPointer&operator=(SmartPointer&rhs){if(&rhs!=reset(rhs.release());return*this;} ②} ④}TYPE*release(void){TYPE*p=m_p;m_p=NULL;returnp;}voidreset(TYPE*p){if(p!=m_p){deletem_p;m_p=p;}}TYPE*正确答案returnreturnreturnreturn正确答案正确答案returnreturnreturnreturn正确答案在一个子类对象的实例化过程中，构造函数的执行顺序是DclassVisitor{virtualboolvisit(int //virtualboolvisit(double //classValidVisitor:publicVisitor{boolvisit(int //classMyValidVisitor:publicValidVisitor{boolvisit(double //4个版本的visit 关系正确答案 关系 关系 关 关系classDog{Dog(intage=0):m_age(age){}virtual~Dog(void){}friendostream&operator<<(ostream&os,constDog&dog){returnos<<dog.m_age; intclassChihuahua:publicDog{Chihuahua(intage=0,constchar*name=NULL) ①m_name(strcpy(newchar[strlen(name?name:"")+1],name?name:""))~Chihuahua(void){}Chihuahua(constChihuahua&chh) ②m_name(strcpy(newchar[strlen(chh.m_name?chh.m_name:"")+1],chh.m_name?chh.m_name:"")){}Chihuahua&operator=(constChihuahua&chh){if(&chh!=this){③char*name=strcpy(newchar[strlen(chh.m_name?chh.m_name:"")+1],chh.m_name?chh.m_name:"");delete[]m_name;m_name=}return}friendostream&operator<<(ostream&os,constChihuahua&chh){returnos<< <<","<<chh.m_name;}char*m_ageDogDog正确答案 空m_ageDogDog正确答案 B.m_age=chh.m_ageC.Dog::operator=(chh)D.static_cast<Dog>(*this)=chh 空static_cast<constDog&>(chh)C.((Dog*)&chh)->m_age正确答案classBase{Base(void):m_buf(newchar[1024])~Base(void){release();}virtualvoidrelease(void){if(m_buf){delete[]m_buf;m_buf=NULL;}}char*classDerived:publicBase{Derived(void):m_data(newint[256])~Derived(void){release();}voidrelease(void){if(m_data){delete[]m_data;m_data=NULL;}}int*intmain(void)Base*base=newDerived;deletebase;return}在上面的代码中，deletebaseBase类的析构函数被调用，该析构函数会调用虚函数m_datam_buf，成述论点是否正确？正确答案StackUnderflowex("whenpop");throwthrownewStackUnderflow("whenthrowStackUnderflow("when正确答案classException{virtualvoidupdate(void)throw();//Updatethestatusofexception…classOutofMemory:publicException{voidupdate(void)throw…以及可能异常的函数voidprocess(void)…throwOutofMemory…}try{process();}catch(Exceptionex)ex.update();}try{process();catch(OutofMemoryex)…ex.update();}try{process();catch(Exception&ex)…}try{process();catch(Exception&ex){…}catchOutofMemory&ex设有intx=123，语 “”cout<<setw(8)<<showpos<<x<<cout<<setw(8)<<showpos<<internal<<x<<cout<<setw(8)<<showpos<<left<<x<<cout<<showpos<<internal<<x<<正确答案//密钥：单字节伪随机整数[0//加密：密文字节=明文字节^//：明文字节=密文字节^密constsize_tBUFSIZE=intXor(constchar*pszSrc,constchar*pszDst,unsignedcharucKey){ifstreamifs( ①);if(!ifs)cout<<"Unabletoopen"<<pszSrc<<endl;return-1;}ofstreamofs( ②);if(!ofs){cout<<"Unabletoopen"<<pszDst<<endl;ifs.close();return-}char*pcBuf=NULL;try{pcBuf=new}catch(bad_alloc&ex)cout<<ex.what()<<endl;ofs.close();ifs.close();return-1;}while(ifs.read ③))for(inti=0;i<BUFSIZE;i++)pcBuf[i]^=ucKey; ④}if(!ifs.eof cout<<"Unabletoread"<<pszSrc<<endl;delete[]pcBuf;ifs.close();return-1;}for(size_ti=0;i<ifs.gcount();i++)pcBuf[i]^=ucKey;ofs.write( ⑤);delete[]pcBuf;ofs.close();ifs.close();return0;}intEncrypt(constchar*pszPlain,constchar*pszCipher){srand(time(NULL));unsignedcharucKey=rand()%256;if(Xor( ⑥)<0)return-cout<<"Key:"<<(unsignedint)ucKey<<endl;return0;}intDecrypt(constchar*pszCipher,constchar*pszPlain,unsignedcharucKey){returnXor( ⑦);}intmain(intargc,char*argv[]){if(argc<3){cout<<"Usage:"<<argv[0]<<"<plain_file><cipher_file>"<<endl;cout<<"Usage:"<<argv[0]<<"<cipher_file><plain_file><key>"<<endl;return-1;}if(argc<returnEncrypt(argv[1],argv[2]);returnDecrypt(argv[1],argv[2],atoi(argv[3]));return0;}B.pszDst,ios::binary正确答案B.pszDst,ios::binary正确答案A.pcBuf,BUFSIZEB.pcBuf,sizeof(pcBuf)正确答案A.pcBuf,BUFSIZEB.pcBuf,sizeof(pcBuf)C.pcBuf,strlen(pcBuf)正确答案A.pcBuf,BUFSIZEB.pcBufsizeofpcBuf)C.pcBuf,strlen(pcBuf)D.pcBuf,ifs.gcount()A.pszSrc,pszDst,ucKeyB.pszCipher,pszPlain,ucKeyC.pszDst,pszSrc,ucKeyD.pszPlain,pszCipher,ucKeyA.pszSrc,pszDst,ucKeyB.pszCipher,pszPlain,ucKeyC.pszDst,pszSrc,ucKeyD.pszPlain,pszCipher,ucKeyC++I/O流：I/O流顶级类是I/O输出类是I/OI/OI/O在队列第i个元后插入一个元p所指向的结点后面插入指针qp=q;p-B.p->next=q;q->next=p;正确答案structnode{intdata;structnode*structnode*func_1(structnode*head,intdata){if(!head)if(head=(structnode*)calloc(1,sizeof(structnode)))head->data=data;elsestructnode*for(p=head;p->next;p=p->if(p->next=(structnode*)calloc(1,sizeof(structnode)))p->next->data=data;}return}structnode*func_2(structnode*head){if(head&&head->next){structnode*this=structnode*next=this->next;head=func_2(next);next->next=this;this-