C语言程序设计(何钦铭颜晖著)高等教育出版社第七章课后答案

练习7-1^include<stdio.h>voidmain()inti,n;doublea[10]7sum=0;printffEntern/x输入•个正整数n*/scanf(n%d'\&n);printf("Enter%dnumbers?\n",n);/*n个数,存储右数Ha+*/fbr(i=O;i<n;i++)scanff'%lf'.&a[i]);产求n个数的之和可tcr(i=0;i<n;i++)sum=sum+a[i];printffTheaverageis=%0.2lf\n",sum/n);i*输出平均值*/include<stdio.h>voidmain()\€Jimina[10];printffEnternI*输入一个正整数n♦/scanfT%cT&n);printffEnter%dintegers:\n".n);/*输入n个整我，存储左数组a中*/tcr(i=0:i<n;i++)scanf(”％d”,&a[i]);voidmam()f\*intijndcxjnax^.aflOJjcmp;printtfEntern:”)；戶输入一个正整数n*/scanffW.&n);个n入输/**/aprintt('Entcr%dintegers:\n个n入输/**/a产求最大数所在下标index,并输岀最大值及其位置勺index=O;fcr(i=O:i<n;i++)if(a[i]>a[mdex])index=i;printffThemaxis%d.thepositionisW\n",a[index],index);产交换最丈值与最后一人数的位置巧temp=a[index|;a[index]=a[n-l];ahl]=tcmp;/'*输tl交换后的n个数*/'fcni=0;i<n;i++)printffn%8d^[i]);printf(,，\nH);}练习7-7include<stdio.h>voidmain()zI4/•intiin5a[10][l0lsum=0;printffTntern产输入一个正整数n♦/fcr(i=O:i<n-l;i+~)fbr(j=O;j<n-l;j卄)ifTi+j!=n-l)sunn-=a[i][j];printf("%d'\n",sum);产输出结果勺}练习7-9★include<stdio.h>intday_of_vear(intyearjntmonth,intday):产函数声明勺voidmain()intyear,monih^ay,result;printffEnteradate(year.month,day)/*输入一个日期(含年、月、日)*/scanfT%d%d%dl&year&month.&day);resuk=day_cf>ear(year1iTionth.day);产调隹day_of^year函数勺printf("%d\n",result);川输出结果可}intday^vear(intyear,intmonth,intday)z\€Iintk.lcap;inttab[2][13]={{031,28,31,30,31,30,3131303,30,31},{031,29,31,30,31,30：3131,3031,30,31}}泸级组初始化,将每月的天数赋值给数則产判断闰年，当year是匡年时，lcap=l；year是非闰年时，leap=0*/lcap=(ycar%4==0&&year%100=0)(ycar%400=0);voidmain()inti.count;charstr[8C'],ch;产输入-个以回车结東的字符串勺printf(Tnterastring:N);i=0;whilc((sfiFgc【char())=\町i++:str[i]=W；/锵结束符妙存入数组勺尸输入一个字符到ch中号ch=getchar();尸求字符串str中ch字符出现的欢数甲fcr(count=0j=0;str[i]!-\0';i++)ifUtr[[=ch)coimt++;printf(count=?zod\n",count);产输凶该字符旳fcr(i=0:str[i]!='\0';i-H)putchar(str[i]);printf("\n");}习题7-1include<stdio.h>voidmain()z\intijndcx1Jndcx2,n,a[10],tcmp;printff'Entern/*输入―个正整数n*/scantr%d,f.&n):if(a[i]>a[indcxl])indcxl=i;it(a[i]<a[index2])index2=i;胶换位置：与晰一个数交慕虽小值与第一个数交埶temp=a[indexr；a[indexl]=a[n-l];a[n-l]=temp;tcmp=a[indcx2：;a'indcx2]=a[Oj;a"0]=tcmp;严输岀交换后的n个数*/fbrfi=O:i<n;i++)printfr%8d",a[i]);printf('\n");}习题7—2include<stdio.h>voidmain()f\intij.index.n.a[10]>temp;printff'Entern/*输入一个正整数n♦/scanfT%(T・&n);聲

个n入输/**/aprintfCEntcr%dintegers:\n聲

个n入输/**/a产用选择法排序巧fcr(i=O;i<n-l;i++){indcx=i;伽(H+咏n;j++)ifFa[il<a[indexDindex=i:printf(v\nn);i习题7—3^/include<stdio.h>voidmain()z\4iintij.n.a[6][6],flag;printfC'Entern:”)；/*输入一个正整数n*/scanfT%d”.&n);printffEnter%dintegers:\n".n);/*输入一个n阶方阵,存绪在数组a中*/fbr(i=O;i<n;i++)forCi=0;j<n：i++)scanff%d"：&a[i][j]);产判断a[n][n]是否上三角矩阵,当flag=h表示上三角矩阵，当flag=O,表示非上三角加flag=l;fbr(i=O;i<n-l;i++)forCi=0;j<i;j^)iffa[i][j]!=O){flag=O;break;}严根据flag值输击结对卩ri呗"YES'n");elseprin(『NO'\n");}习题7—4"include<stdio.h>voidmain()intij.mlnla[6][6],sum[6]={O,O,O,OA0j;产求矩阵a+各行元素之和，并存储在数组sum中杓ft}T(i=O;i<m;i++)fbr(j=O;j<nj-H-)sum[i>=a[i][j];严输出结果勺fbT(i=O;i<m;i++)printfrsumofthe%dlineis%d\n：i,siim|i]);^/include<stdio.h>voidmain。*inti,j.n.a[6][6],max.min,flag;printff'Entern:”)；产输入一个正整数n*/scanfT%(r・&n);printffEnter%dintegers:\n,r.n);/*输入〜个n阶方阵,存楮在数组a中*/for(i=0;i<n;i-H*)伽(H；j<n計+)scanf(M%d；&a[i]OJ)；产找鞍点,-Iflag=l,表示找至.了鞍点，当flag=0,表示未找到竣点*/flag=O;fcr(i=0;i<n;i++)fi广找第i行中最大值所在列下标max*/max=0;伽(j=O;j<n:j十十)iffa[i][j]>a[i][max]imax=j;咳第max列中最小值所在行下标min*/min=0;elseprintfl[wNO\nn);习题7—6^include<stdio.h>voidmain()tKinti,j;charstr[8O];尸输入一个以回车结束的字符串可printff'Enterastring:i=0;while((sirj]=geichar())!-\n')i++:str[i]=W;产将结束符如存入数组勺产逆序筍出字符串sir中的字符号fcnj=i-lj>=€';j-)putchar(str[j]);printff\n");习题7—7include<stdio.h>voidmain()\4Iintijxount:charstr[8O];尸输入一个以回车结束的字㈣printffEnterastring:");i=0;printf(*count=%d\nH,count);习题7—8include<stdio.h>voidmain()z\好9\inti,count;charstr[8O];产输入一个以回车结束的字符翰printffEnterastring:i=0;whilc((strj]=gctchar())!-\n')i++:str[iF。；/'*将结東符切存入数组幷产按规则替换沟讳str中你写字母，并输出替换!訓字符串勺for(count=0,i=0^tr[i]!-\0';i++)fIif(str[i]>='A'&&str[i]<=,Z,tor[i]=,A,+('Z,-str[i]);putchar(str[i]l:}printf("\n");include<stdio.h>intij;doublenum10:oldstrfiJ^OoldstrfiJ^O1;/*将结束符⑷存入数组糾产过滤去字符自str中的非十六制字符,并输出新十六制字符串勺’printfT十六进制数』);fcni=0j=0;cldstr[ij-\0';i++)ift(oldstr[i]>-0'&&old5tr[i]<=9‘)(oldsir;]>='^&&oldstr[i]<-F,)||(oldstr[i]>-a'&&oldstr[i]<-f))zI<ncwstr[j]=oldstr[i];putchar(newstr|j]);j"；}news吨]汕0';/*将结束符切存入数级勺产将字符串newstr"啲"制数转换为十进制妙fcr(num_10=0,i=0;newstr[i]!