#include<stdio.h>                                              #include<stdio.h>
void main()                                                    void main()
{                                                           {
    int a[4][4],b[4][4],i,j;                                   int a[4][4],b[4][4],i,j;
    printf("input 16 number");                                 printf("input 16 number");
    for(i=0;i<4;i++)                                           for(i=0;i<4;i++)
    for(j=0;j<4;j++)                                           for(j=0;j<4;j++)
        {                                                   {
            scanf("%d",&a[i][j]);                             scanf("%d",&a[i][j]);
            b[3-j][i]=a[i][j];                                 b[3-j][i]=a[i][j];
        }                                                   }
        printf("array\n");                                   printf("array\n");
        for(i=0;i<4;i++)                                     for(i=0;i<4;i++)
                                                             for(j=0;j<4;j++)
        {                    就是把此处的花括号移到下方去了                     
                    for(j=0;j<4;j++)                                 {
            printf("%6d",b[i][j]);                                printf("%6d",b[i][j]);
            printf("\n");                                         printf("\n");
            
        }                                                     }
}                                                            }

你用的啥编辑器粘出这样的效果。。。

for(i=0;i<4;i++)                                 
                                                         
{                    //就是把此处的花括号移到下方去了
    for(j=0;j<4;j++)                     
        printf("%6d",b[i][j]);                        
    printf("\n");                                 
                                                         
}

for(i=0;i<4;i++)
    for(j=0;j<4;j++)
                     
    {
        printf("%6d",b[i][j]);
        printf("\n");

    }

for(i=0;i<4;i++)
{
    for(j=0;j<4;j++)
                     
    {
        printf("%6d",b[i][j]);
        printf("\n");

    }
}

                           
for(i=0;i<4;i++)                                 
                                                         
{//就是把此处的花括号移到下方去了
    for(j=0;j<4;j++)
    {
        printf("%6d",b[i][j]);
    }
    printf("\n");
}

合适的缩进加上补全大括号你就知道为啥了

顺便 你帖代码的格式很不好 虽然我知道你是想展示代码的区别 但你这个也太难看了

for语句默认控制一个语句，左边的程序for语句控制的是printf("%6d",b[i][j]);这句，而右边的程序由于是用了花括号使得for语句控制了printf("%6d",b[i][j]);及
  printf("\n");这句，两个程序就不同了

知道大括号是干啥的吗？位置不同当然效果不一样

总有那身价贱的人给作业贴回复完整的代码

...

经过5楼的讲解，懂了点