C語言程序設(shè)計何欽銘顏暉著高等教育出版社第七章課后答案

1、練習(xí)71#include <stdio.h>void main()int i,n;double a10,sum=0;printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d numbers :n",n); /* 輸入n個數(shù)，存儲在數(shù)組a中 */for(i=0;i<n;i+)scanf("%lf",&ai);/*求n個數(shù)的之和*/for(i=0;i<n;i+)sum=sum+ai;printf(&quo

2、t;the average is =%0.2lfn",sum/n); /* 輸出平均值 */練習(xí)72#include <stdio.h>void main()int i,n,a10;printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入n個整數(shù)，存儲在數(shù)組a中 */for(i=0;i<n;i+)scanf("%d",&ai);/*按逆序輸出n個數(shù)*/

3、for(i=0;i<n;i+)printf("%8d",an-1-i);printf("n");練習(xí)74#include <stdio.h>void main()int i,index,max,n,a10,temp;printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入n個整數(shù)，存儲在數(shù)組a中 */for(i=0;i<n;i+)scanf(&

4、quot;%d",&ai);/*求最大數(shù)所在下標(biāo)index，并輸出最大值及其位置*/index=0;for(i=0;i<n;i+)if(ai>aindex)index=i;printf("the max is %d, the position is %dn",aindex,index);/*交換最大值與最后一個數(shù)的位置*/temp=aindex;aindex=an-1;an-1=temp;/*輸出交換后的n個數(shù)*/for(i=0;i<n;i+)printf("%8d",ai);printf("n")

5、;練習(xí)77#include <stdio.h>void main()int i,j,n,a1010,sum=0;printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入一個n階方陣，存儲在數(shù)組a中 */for(i=0;i<n;i+)for(j=0;j<n;j+)scanf("%d",&aij);/*求n階方陣中除副對角線、最后一列和最后一行外所有元素之和*

6、/for(i=0;i<n-1;i+)for(j=0;j<n-1;j+)if(i+j!=n-1)sum+=aij;printf("%dn",sum); /*輸出結(jié)果*/練習(xí)79#include <stdio.h>int day_of_year(int year,int month,int day); /*函數(shù)聲明*/void main()int year,month,day,result;printf("enter a date(year,month,day) :"); /* 輸入一個日期（含年、月、日） */scanf("

7、;%d%d%d",&year,&month,&day);result=day_of_year(year,month,day); /*調(diào)用day_of_year函數(shù)*/printf("%dn",result); /*輸出結(jié)果*/int day_of_year(int year,int month,int day)int k,leap;int tab213=0,31,28,31,30,31,30,31,31,30,31,30,31,0,31,29,31,30,31,30,31,31,30,31,30,31; /*數(shù)組初始化，將每月的天數(shù)賦值給數(shù)

8、組*/*判斷閏年，當(dāng)year是閏年時，leap=1；當(dāng)year是非閏年時，leap=0*/leap=(year%4=0 && year%100!=0) | (year%400=0);/*計算天數(shù)*/for(k=1;k<month;k+)day+=tableapk;return day;練習(xí)711#include <stdio.h>void main()int i,count;char str80,ch;/*輸入一個以回車結(jié)束的字符串*/printf("enter a string: ");i=0;while(stri=getchar()!=

9、'n')i+;stri='0' /*將結(jié)束符'0'存入數(shù)組*/*輸入一個字符到ch中*/ch=getchar();/*求字符串str中ch字符出現(xiàn)的次數(shù)*/for(count=0,i=0;stri!='0'i+)if(stri=ch)count+;printf("count=%dn",count);/*輸出該字符串*/for(i=0;stri!='0'i+)putchar(stri);printf("n");習(xí)題71#include <stdio.h>void m

10、ain()int i,index1,index2,n,a10,temp;printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入n個整數(shù)，存儲在數(shù)組a中 */for(i=0;i<n;i+)scanf("%d",&ai);/*求最大數(shù)、最小數(shù)所在下標(biāo)index1、index2*/index1=0;index2=0;for(i=0;i<n;i+)if(ai>aind

11、ex1)index1=i;if(ai<aindex2)index2=i;/*交換位置：最大值與最后一個數(shù)交換，最小值與第一個數(shù)交換*/temp=aindex1;aindex1=an-1;an-1=temp; temp=aindex2;aindex2=a0;a0=temp;/*輸出交換后的n個數(shù)*/for(i=0;i<n;i+)printf("%8d",ai);printf("n");習(xí)題72#include <stdio.h>void main()int i,j,index,n,a10,temp;printf("ente

12、r n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入n個整數(shù)，存儲在數(shù)組a中 */for(i=0;i<n;i+)scanf("%d",&ai);/*用選擇法排序*/for(i=0;i<n-1;i+)index=i;for(j=i+1;j<n;j+)if(aj<aindex)index=j;temp=aindex;aindex=ai;ai=temp;/*輸出排序后的n個數(shù)*/for(i=

13、0;i<n;i+)printf("%8d",ai);printf("n");習(xí)題73#include <stdio.h>void main()int i,j,n,a66,flag; printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入一個n階方陣，存儲在數(shù)組a中 */for(i=0;i<n;i+)for(j=0;j<n;j+)scan

14、f("%d",&aij);/*判斷ann是否上三角矩陣，當(dāng)flag=1，表示上三角矩陣，當(dāng)flag=0，表示非上三角矩陣*/flag=1;for(i=0;i<n-1;i+)for(j=0;j<i;j+)if(aij!=0)flag=0;break;/*根據(jù)flag值輸出結(jié)果*/if(flag=1)printf("yesn");else printf("non");習(xí)題74#include <stdio.h>void main()int i,j,m,n,a66,sum6=0,0,0,0,0,0; prin

15、tf("enter m and n :"); /* 輸入兩個正整數(shù)m和n */scanf("%d%d",&m,&n);printf("enter %d integers :n",m*n); /* 輸入一個m*n階矩陣，并存儲在數(shù)組a中 */for(i=0;i<m;i+)for(j=0;j<n;j+)scanf("%d",&aij);/*求矩陣a中各行元素之和，并存儲在數(shù)組sum中*/for(i=0;i<m;i+)for(j=0;j<n;j+)sumi+=aij;/*輸

16、出結(jié)果*/for(i=0;i<m;i+)printf("sum of the %d line is %dn",i,sumi);習(xí)題75#include <stdio.h>void main()int i,j,n,a66,max,min,flag; printf("enter n :"); /* 輸入一個正整數(shù)n */scanf("%d",&n);printf("enter %d integers :n",n); /* 輸入一個n階方陣，存儲在數(shù)組a中 */for(i=0;i<n;i+

17、)for(j=0;j<n;j+)scanf("%d",&aij);/*找鞍點，當(dāng)flag=1，表示找到了鞍點，當(dāng)flag=0，表示未找到鞍點*/flag=0;for(i=0;i<n;i+)/*找第i行中最大值所在列下標(biāo)max*/max=0;for(j=0;j<n;j+)if(aij>aimax)max=j;/*找第max列中最小值所在行下標(biāo)min*/min=0;for(j=0;j<n;j+)if(ajmax<aminmax)min=j;if(min=i)flag=1;break;/*根據(jù)flag值輸出結(jié)果*/if(flag=1)p

18、rintf("鞍點是a%d%d=%dn",min,max,aminmax);else printf("non");習(xí)題76#include <stdio.h>void main()int i,j;char str80;/*輸入一個以回車結(jié)束的字符串*/printf("enter a string: ");i=0;while(stri=getchar()!='n')i+;stri='0' /*將結(jié)束符'0'存入數(shù)組*/*逆序輸出字符串str中的字符*/for(j=i-1;j&g

19、t;=0;j-)putchar(strj);printf("n");習(xí)題77#include <stdio.h>void main()int i,j,count;char str80;/*輸入一個以回車結(jié)束的字符串*/printf("enter a string: ");i=0;while(stri=getchar()!='n')i+;stri='0' /*將結(jié)束符'0'存入數(shù)組*/*統(tǒng)計字符串str中大寫輔音字母的個數(shù)*/for(count=0,i=0;stri!='0'i+)

20、if(stri>='a' && stri<='z' && stri!='a' && stri!='e' && stri!='i' && stri!='o' && stri!='u')count+;printf("count=%dn",count);習(xí)題78#include <stdio.h>void main()int i,count;char

21、str80;/*輸入一個以回車結(jié)束的字符串*/printf("enter a string: ");i=0;while(stri=getchar()!='n')i+;stri='0' /*將結(jié)束符'0'存入數(shù)組*/*按規(guī)則替換字符串str中的大寫字母，并輸出替換后的字符串*/for(count=0,i=0;stri!='0'i+)if(stri>='a' && stri<='z')stri='a'+('z'-stri);putchar(stri);printf("n");習(xí)題79#include <stdio.h>void main()int i,j;double num_10;char oldstr80,newstr80;/*輸入一個以回車結(jié)束的字符串*/printf("enter a string: ");i=0;while(oldstri=getchar()!='n')i+;oldstri='0' /*將結(jié)束符'0'存入數(shù)組*/*過