书后习题答案--第7章

第7章一、（1）D注：选项排版有误，需调整如下。

A) int a(10);B) int n=10,a[n];C) int n;scanf("%d",&n);int a[n];D) #define SIZE 10int a[SIZE];（2）B（3）D（4）D（5）A二、（1）1（2）12345（3）t*M（4）70789198三、（1）i-- i>=1 i注：内容超纲，可在学完指针后再做。

（2）i<=9 i<=9 i%3==0四、（1）int a[3]={0};for(i=1;i<3;i++) a[0]=a[0]+a[i];（2）for(i=0;i<d;i++)t[2*d]='\0’scanf(“%s”,s)五、（1）升序排列数组元素。

1 2 3 4 5 5 6 7 8 9（2）33 33 27 22 12 11 -1 -8 -8 -1 11 12 22 27 33 33 六、（1）#include<stdio.h>void main(){int a[10],i,x,y;printf("please input the number:\n");for(i=0;i<10;i++)scanf("%d",&a[i]);x=a[0];y=a[0];for(i=1;i<10;i++){if(a[i]>x)x=a[i];if(a[i]<y)y=a[i];}printf("the answer is %d",x-y);}（2）#include<stdio.h>void main(){int a[10],i,j,k,t;printf("please input the numbers:\n"); for(i=0;i<10;i++)scanf("%d",&a[i]);for(i=0;i<=8;i++){k=i;for(j=i+1;j<=9;j++)if(a[j]>a[k])k=j;t=a[k];a[k]=a[i];a[i]=t;}for(i=0;i<=9;i++)printf(" %d",a[i]);}（3）#include <stdio.h>void main(){int a[7]={3,5,7,9,11,23};int b,i,k;scanf("%d",&b);a[6]=b;i=5;while(b<a[i]&&i>=0){a[i+1]=a[i];a[i]=b;i--;}printf("cha ru hou de shu zu \n"); for(i=0;i<7;i++)printf("%d ",a[i]);}（4）#include<stdio.h>void main(){int a[10],i,j,k;printf("please input the numbers:\n");for(i=0;i<10;i++)scanf("%d",&a[i]);printf("please input the aim number:\n"); scanf("%d",&k);for(i=0;i<=9;i++)if(a[i]==k)break;if(i>9)printf("NO\n");elseprintf("YES\n");}（5）#include<stdio.h>void main(){int i,j;for(i=1;i<=4;i++){for(j=1;j<=i-1;j++)printf(" ");for(j=1;j<=9-2*i;j++)printf("*");printf("\n");}}（6）#include<stdio.h>void main(){int a[10],i,t;printf("please input the numbers:\n"); for(i=0;i<10;i++)scanf("%d",&a[i]);for(i=0;i<10/2;i++){t=a[i];a[i]=a[10-1-i];a[10-1-i]=t;}for(i=0;i<10;i++)printf(" %d",a[i]);}（7）#include<stdio.h>void main(){int a[5][5]={0},i,j;for(i=0;i<=4;i++)a[i][0]=a[i][i]=1;for(i=2;i<=4;i++)for(j=1;j<i;j++)a[i][j]=a[i-1][j]+a[i-1][j-1];for(i=0;i<=4;i++){for(j=0;j<=i;j++)printf(" %3d",a[i][j]);printf("\n");}}（8）#include<stdio.h>void main(){char c[5][5]={'\0'};int i,j;for(i=0;i<5;i++)for(j=i;j<5;j++)c[i][j]='*';for(i=0;i<5;i++){for(j=0;j<5;j++)printf("%c",c[i][j]);printf("\n");}}（9）#include<stdio.h>void main(){int a[3][3],i,j,x;printf("please input the numbers:\n"); for(i=0;i<3;i++)for(j=0;j<3;j++)scanf("%d",&a[i][j]);x=0;for(i=0;i<3;i++)x=x+a[i][i];printf("the answer is %d\n",x);}（10）#include<stdio.h>void main(){int a[10]={10,9,8,7,6,5,4,3,2,1},l,r,m,k; printf("please input the numbers:\n"); scanf("%d",&k);l=0;r=9;m=(1+r)/2;while(l<=r)if(a[m]==k)break;else{if(k>a[m])r=m-1;elsel=m+1;m=(l+r)/2;}if(l<=r)printf("\n YES ");elseprintf("\n NO ");}（11）#include<stdio.h>#include <string.h>void main(){char s[80];int n=0;gets(s);while(s[n])n++;printf("\n length = %d ",n);}（12）#include<stdio.h>#include <string.h>void main(){char s1[80],s2[80];int i,n;gets(s1);gets(s2);i=0;while(s1[i]&&s2[i]&&s1[i]==s2[i])i++; if(!s1[i]||s1[i]<s2[i])n=-1;if(!s2[i]||s1[i]>s2[i])n=1;if(!s1[i]&&!s2[i])n=0;printf("\n jie guo shi %d ",n);}（13）#include<stdio.h>void main(){int a[10],i,j,x;for(i=0;i<10;i++)scanf("%d",&a[i]);for(j=0;j<9;j++)for(i=0;i<9-j;i++)if(a[i]>a[i+1]){x=a[i];a[i]=a[i+1];a[i+1]=x;}for(i=0;i<10;i++)printf("%4d",a[i]);}（14）#include <stdio.h>void main(){int a[5][5];int i,j;for(i=0;i<5;i++)for(j=0;j<5;j++)if(i<=j)a[i][j]=1;elsea[i][j]=i-j+1;for(i=0;i<5;i++){for(j=0;j<5;j++)printf("%2d",a[i][j]);printf("\n");}}（15）#include<stdio.h>void main(){int a[3][4],i,j,x,l,r;for(i=0;i<3;i++)for(j=0;j<4;j++)scanf("%d",&a[i][j]);x=a[0][0];l=r=0;for(i=0;i<3;i++)for(j=0;j<4;j++)if(a[i][j]>x){x=a[i][j];l=i;r=j;}printf("Max number is %d,position is %d,%d\n",x,l,r); }。