c++primerplus第六版第七章编程练习

c++primerplus第六版第七章编程练习1.⽤函数计算输⼊的两个数的调和平均数，结果返回给main//练习7.1main输出结果函数计算输⼊的调和平均数，#include<iostream>usingnamespacestd;doublecount(double,double);intmain(){doublex=0.0,y=0.0;cout<<"Pleaseenterthevalueofxandy:";//cin>>x>>y;while(cin>>x>>y){if(x==0||y==0){break;}doublevalue=count(x,y);cout<<"TheHarmonicmeanofxandyis:"<<value<<endl;cout<<"Continue:";}cout<<"Bye"<<endl;system("pause");return0;}doublecount(doublem,doublen){doubletemp;temp=2.0*m*n/(m+n);returntemp;}把while的判断句式改成cin看看？很好玩哦2.处理⾼尔夫成绩输⼊，使⽤3个数组处理函数分别对应输⼊、显⽰和计算平均成绩的操作。//练习7.2⾼尔夫成绩处理程序//最多输⼊10个成绩，存储在数组中//使⽤3个函数分别对应输⼊、显⽰和计算平均成绩//⾼尔夫计分准则是杆数，⽤多少杆打完18个洞，国际标准是72杆，如果打出少于72杆（⽐如70杆，那就是-2）#include<iostream>#include<string>usingnamespacestd;constintMax=10;intfill_arr(int[],int);voidshow_grade(constint[],int);doublecount_grade(constint[],int);intmain(){int*fraction=newint[Max];intm;cout<<"Howmanyvalidresultsdoyouwanttoenter?";cin>>m;intsize=fill_arr(fraction,m);if(size>0){doubleaverage_grade=count_grade(fraction,size);show_grade(fraction,size);cout<<"Theaverageofthegradeis"<<average_grade<<'.'<<endl;}delete[]fraction;system("pause");return0;}intfill_arr(intarr[],intn){cout<<"Pleaseentergrade(qtoquit)"<<endl;inttemp,i;for(i=0;i<n;i++){cout<<'#'<<i+1<<':';cin>>temp;if(!cin){cin.clear();break;}arr[i]=temp;}returni;}voidshow_grade(constintarr[],intn){for(intj=0;j<n;j++){cout<<"#"<<j+1<<':'<<arr[j]<<'';}cout<<endl;}doublecount_grade(constintarr[],intn){doubletemp;intsum=0;for(intk=0;k<n;k++){sum+=arr[k];}temp=(double)sum/n;returntemp;}上⾯是两个输出结果，⼀个是限定输⼊内的结果（前图），另外⼀张是中途退出输出的结果。3.编写结构体box，并编辑两个处理结构体元素的函数//7.3练习结构体处理//包含两个函数show_val（）和reset（）//前者按值传递结构体并显⽰值，后者参量为结构体地址，重置其中volume为其他三维长度的乘积#include<iostream>#include<string>usingnamespacestd;constintMax=10;structbox{charmaker[40];floatheight;floatlength;floatwidth;floatvolume;};voidshow_val(constbox);voidreset(box*p);intmain(){boxbox1{"JohnWick",10.0,100.0,40.0,0.0};show_val(box1);reset(&box1);cout<<endl;show_val(box1);system("pause");return0;}voidshow_val(constboxb1){cout<<"Maker:"<<b1.maker<<endl;cout<<"#Length:"<<b1.length<<endl;cout<<"#Width:"<<b1.width<<endl;cout<<"#Leight:"<<b1.height<<endl;cout<<"#Volume:"<<b1.volume<<endl;}voidreset(box*p){p->volume=p->length*(p->height)*(p->width);}4.重写程序清单7.4的计算彩票中奖⼏率程序//练习7.4重写程序清单7.4//从域号码（1-47）中选取5个号码，再从第⼆区间（1-27）中选⼀个，全部猜中才算中奖//中奖⼏率：前者⼏率和后者⼏率的乘积//原程序中只需要调⽤⼀次函数，可改写成调⽤两次并相乘#include<iostream>longdoubleprobability(unsignednumbers,unsignedpicks);intmain(){usingnamespacestd;doubletotal,choices,award=1;intn;cout<<"Howmanytimesdoyouwanttochcice?";cin>>n;//cin.get();cout<<"Enterthetotalnumberofchoicesonthegamecardand\n""thenumberofpicksallowed:"<<endl;inti=0;while((cin>>total>>choices)&&choices<=total){award*=probability(total,choices);if(i>=n-1)break;i++;cout<<"Again(qtoquit):";}cout<<"Youhaceonechancein";cout<<award;cout<<"ofwinning."<<endl;cout<<"Bye."<<endl;system("pause");return0;}longdoubleprobability(unsignednumbers,unsignedpicks){longdoubleresult=1.0;longdoublen;unsignedp;for(n=numbers,p=picks;p>0;n--,p--)result=result*n/p;returnresult;}这是我刚睡醒迷迷糊糊敲的，将就着看吧。5.编写⼀个递归函数来计算阶乘结果//7.5练习定义⼀个递归（递龟）函数来计算阶乘//输⼊⼀个整数n，如果#include<iostream>longfactorial(int);usingnamespacestd;intmain()n>0,n!=n*n-1!则（）{intm=0;longresult=0;cout<<"Howmanytimesdoyouwanttoenter?";cin>>m;for(inti=0;i<m;i++){intinteger;cout<<"#"<<(i+1)<<':';cin>>integer;result=factorial(integer);cout<<"Theresultofthe"<<integer<<"!is"<<result<<'.'<<endl;}system("pause");return0;}longfactorial(intn){longtemp;if(n==0||n==1)temp=1;elsetemp=n*factorial(n-1);returntemp;}6.编写数字数组处理程序//7.6编写⼀个关于double数组的输⼊、显⽰和反转程序练习//三个函数分别对应输⼊、显⽰和反转功能//fill_arrayshow_array（显⽰）和reverse_array（反转）（输⼊）、#include<iostream>#include<iomanip>intfill_array(double*arr,int);voidshow_array(constdouble*arr,int);voidreverse_array(double*arr,int);usingnamespacestd;constintMax=20;intmain(){intm=0;double*number=newdouble[Max];cout<<"Howmanynumbersneedtobeentered?";cin>>m;m=fill_array(number,m);show_array(number,m);reverse_array(number,m);show_array(number,m);delete[]number;system("pause");return0;}intfill_array(double*arr,intn){cout<<"Pleaseenterthenumber.(Entercharacterotherthannumberstoquit)"<<endl;inti=0;cout<<"#"<<i+1<<":";cout<<"#"<<i+1<<":";while(cin>>arr[i]){i++;if(i==n)break;cout<<"#"<<(i+1)<<":";}returni;}voidshow_array(constdouble*arr,intn){cout<<"Thevalueofthearrayis:"<<endl;for(inti=0;i<n;i++){cout<<setw(8);cout<<"#"<<(i+1)<<":"<<arr[i]<<"";if((i+1)%5==0){cout<<endl;}}cout<<endl;}voidreverse_array(double*arr,intn){inttemp;while(n){if(n==1){cout<<"Itisnoneedtoreversethem.";break;}for(inti=0,j=n-1;i<(n/2);i++,j--){temp=arr[i];arr[i]=arr[j];arr[j]=temp;}break;}}上⾯分别是预期数量的输⼊和字符退出的显⽰，程序允许在定期输⼊前进⾏退出。7.改写程序清单7.7//7.7改写程序清7.7的数组处理使之可⽤区间练习//fill_array不返回实际读取数字，⽽是返回尾指针//其他函数可以使⽤这个指针作为参数标识结尾#include<iostream>#include<iomanip>double*fill_array(double*Begin,double*end);//返回指针的函数voidshow_array(constdouble*Begin,constdouble*end);voidrevalue(double*Begin,double*end,doubler);usingnamespacestd;constintMax=5;intmain()intmain(){double*temp;doubleproperties[Max];temp=fill_array(properties,properties+Max);show_array(properties,temp);if(temp!=properties){cout<<"Entertherevaluationfactor:";doublefactor;while(!(cin>>factor)){cin.clear();while(cin.get()!='\n')continue;cout<<"Badinput;enteragain:";}revalue(properties,temp,factor);show_array(properties,temp);}cout<<"Done."<<endl;system("pause");return0;}double*fill_array(double*Begin,double*end){staticdouble*pt;//c++不允许返回局部变量的地址，所以给需要返回的地址进⾏范围拓展doubletemp=0.0;inti=0;for(pt=Begin;pt!=end;pt++,i++){cout<<"Entervalue#"<<(i+1)<<":";cin>>temp;if(!cin){cin.clear();while(cin.get()!='\n')continue;cout<<"Badinput;inputprocessterminated.\n";break;}elseif(temp<0)break;*pt=temp;}returnpt;}voidshow_array(constdouble*Begin,constdouble*end){constdouble*pt;inti=0;cout<<"Thevalueofthearrayis:"<<endl;for(pt=Begin;pt!=end;pt++,i++){cout<<setw(8);cout<<"Property#"<<(i+1)<<":$"<<*pt<<"";if((i+1)%3==0){cout<<endl;}}cout<<endl;}voidrevalue(double*Begin,double*end,doubler){double*pt;double*pt;for(pt=Begin;pt!=end;pt++){*pt=(*pt)*r;}}照抄书本的输⼊，同样的预期输⼊和范围外输⼊，关于返回指针的函数的编写很有意思。8.在不使⽤array类完成程序清单7.15的⼯作，以下两个版本：a.使⽤constchar*数组存储表⽰季度名称的字符串，使⽤double数组存储开⽀；//7.8_a在不使⽤array类完成程序清单7.15练习的⼯作//constchar*double数组存储开⽀使⽤数组存储表⽰季度名称的字符串，使⽤#include<iostream>#include<iomanip>constchar*season[]={"Spring","Summer","Autumn","Winter"};//指向四个字符串的常指针型数组voidfill_array(double*arr);voidshow_array(constdouble*arr);usingnamespacestd;constintsea=4;intmain(){double*sales=newdouble[sea];fill_array(sales);show_array(sales);cout<<"Bye."<<endl;delete[]sales;system("pause");return0;}voidfill_array(double*arr){cout<<"Pleaseenterthesales."<<endl;for(inti=0;i<sea;i++){cout<<season[i]<<":";cin>>arr[i];}}voidshow_array(constdouble*arr){doubletotal=0.0;cout<<endl<<"Thesalesoftheseason."<<endl;for(intj=0;j<sea;j++){cout<<season[j]<<":"<<arr[j]<<endl;total+=arr[j];}cout<<"Thesaleoffourseasonis:"<<total<<"."<<endl;}b.使⽤constchar*数组存储表⽰季度的字符串，并使⽤只包含⼀个成员（⽤于存储开⽀的double数组）的结构。//7.8_b在不使⽤array类完成程序清单7.15练习的⼯作//constchar*double使⽤数组存储表⽰季度的字符串，并使⽤只包含⼀个成员（⽤于存储开⽀的数组）的结构#include<iostream>#include<iomanip>constchar*season[]={"Spring","Summer","Autumn","Winter"};//指向四个字符串的常指针型数组voidfill_array(structexpense*arr);voidshow_array(constexpense*arr);usingnamespacestd;constintsea=4;structexpense{doubleexpen;};intmain(){expense*sales=newexpense[sea];fill_array(sales);show_array(sales);cout<<"Bye."<<endl;delete[]sales;system("pause");return0;}voidfill_array(structexpense*arr){cout<<"Pleaseenterthesales."<<endl;for(inti=0;i<sea;i++){cout<<season[i]<<":";cin>>arr[i].expen;}}voidshow_array(constexpense*arr){doubletotal=0.0;cout<<endl<<"Thesalesoftheseason."<<endl;for(intj=0;j<sea;j++){cout<<season[j]<<":"<<arr[j].expen<<endl;total+=arr[j].expen;}cout<<"Thesaleoffourseasonis:"<<total<<"."<<endl;}9.提供主函数及函数原型，完善函数使其达标。练习//7.9补充程序所⽤函数//constchar*double使⽤数组存储表⽰季度的字符串，并使⽤只包含⼀个成员（⽤于存储开⽀的数组）的结构#include<iostream>intgetinfo(structstudentpa[],intn);voiddisplay1(studentst);voiddisplay2(conststudent*ps);voiddisplay3(conststudentpa[],intn);usingnamespacestd;constintSLEN=30;structstudent{charfullname[SLEN];charhobby[SLEN];intooplevel;};intmain()intmain(){cout<<"Enterclasssize:";intclass_size;cin>>class_size;while(cin.get()!='\n')continue;student*ptr_stu=newstudent[class_size];intentered=getinfo(ptr_stu,class_size);for(inti=0;i<entered;i++){display1(ptr_stu[i]);display2(&ptr_stu[i]);}display3(ptr_stu,entered);delete[]ptr_stu;cout<<"Done."<<endl;system("pause");return0;}intgetinfo(structstudentpa[],intn){intnumbers=0;for(inti=0;i<n;i++){cout<<"student#"<<(i+1)<<":";cout<<"name:";cin.get(pa[i].fullname,SLEN).get();cout<<"Hobby:";cin.get(pa[i].hobby,SLEN).get();cout<<"ooplevel:";cin>>pa[i].ooplevel;while(cin.get()!='\n')continue;numbers++;}returnnumbers;}voiddisplay1(studentst){cout<<endl;cout<<"name:"<<st.fullname<<endl;cout<<"Hobby:"<<st.hobby<<"ooplever:"<<st.ooplevel<<endl;}voiddisplay2(conststudent*ps){cout<<endl;cout<<"name:"<<ps->fullname<<endl;cout<<"Hobby:"<<ps->hobby<<"ooplever:"<<ps->ooplevel<<endl;}voiddisplay3(conststudentpa[],intn){cout<<endl;for(inti=0;i<n;i++){cout<<"#"<<(i+1)<<""<<pa[i].fullname<<endl;cout<<"Hobby:"<<pa[i].hobby<<"ooplevel:"<<pa[i].ooplevel<<endl;}}10.按题⽬要求，编写通过函数指针作为参数来调⽤其他函数的calculate函数，另外两个add函数和multipy函数进⾏计算，主函数循环调⽤calculate计算输出结果，有点赶⼯，就没有细致测试，各位同僚可以试⼀下浮点数。//7.10练习编写函数调⽤程序//练习7.10编写函数调⽤程序//calculate函数负责调⽤add函数和multipy函数#include<