Question

C语言题目。。帮帮忙（很急），真的非常谢谢拉。。。

四、程序：阅读以下程序，分别写出输出结果
21．swap (int x[2])
{int temp;
temp=x[0];x[0]=x[1];x[1]=temp;
}
main()
{int a[2];
a[0]=5;a[1]=10;
swap(a);
printf("%d,%d",a[0],a[1]);
}
输出结果为：__________________
22．main()
{static char a[]="123xyz456xyz";
int count[128],i;
char *p=a;
for (i=0;i<127;i++)
count[i]=0;
while (*p) count[*p++]++;
for (i=0;i<127;i++)
if (count[i]) printf("%c[%d]\n",(char)i,count[i]);
}
输出结果为：___________________
23．#include <stdio.h>
main()
{static int sq[3][3]={0,0,0,.....,0};
int i,j,k;
i=1;j=2;
sq[i][j]=1;
for (k=2;k<=9;k++)
{i++;j++;
if (i>2 && j>2) {i--;j-=2;};
else if (i<=2 && j>2) j=0;
else if (i>2 && j<=2) i=0;
else if (i<=2 && j<=2 && sq[i][j]!=0) {i--;j-=2;};
sq[i][j]=k;
}
for (i=0;i<3;i++)
for (j=0;j<3;j++)
printf("%5d",sq[i][j]);
printf("\n");
}
输出结果为：___________________
24．struct str1
{char c[5];
char *s;}
main()
{static struct str2 {struct str1 sr; int d;}s2={"LPQ","RST",3245};;
static struct str1 s1[2]={{"ABCD","EFGH"},{"MJK","XYZ"}};
static struct str1 *p[]={&s1[0],&s1[1]};
printf("%c\n",p[0]->c[1]);
printf("%s\n",++p[0]->s);
printf("%c\n",s2.sr.c[2]);
printf("%d\n",s2.d+1);
}
输出结果为：_____________________
改错题：请将错误的地方订正过来20．＃include“stdio.h”
main()
{int score;
char flag='y';
while (flag='y'||flag='Y')
{while(1)
{printf("input score:");
scanf(“%d”,score);
if (score<0 && score>100) break;
}
switch (score%10)
{ case 10:
case 9: putchar('A'); break;
case 8: putchar('B'); break;
case 7: putchar('C'); break;
case 6: putchar('D'); break;
default: putchar('E'); break; }
printf("y-Continue,anykey-Exit\n");
getchar(flag);}}
帮帮忙。。谢谢了

Answer 1

前面几题自己运行吧，太懒了，最后一题修改如下：
#include"stdio.h"//双引号为英文的
main()
{int score;
char flag='y';
while ((flag='y')||(flag='Y'))//加括号
{while(1)
{printf("input score:");//双引号为英文的
scanf("%d",&score);//&
if (score<0 || score>100) break;//&& -> ||
}
switch (score%10)
{ case 10:
case 9: putchar('A'); break;
case 8: putchar('B'); break;
case 7: putchar('C'); break;
case 6: putchar('D'); break;
default: putchar('E'); break; }
printf("y-Continue,anykey-Exit\n");
getchar(flag);}}