改好了,看看吧：
#include "stdio.h"
#include "conio.h"
void main()
{int ch;
printf("Please enter a year:");
scanf("%d",&ch);
if((ch%4==0&&ch%100!=0)||(ch%400==0))
printf("%d is a leap year\n",&ch);
else
printf("%d is not a leap year",ch);
getch();
}

%   和   /  要分清.

应该是求余吧，不应该是除ch％4～～

#include <stdio.h>
#include <stdlib.h>
main()
{
      int ch;
      printf("Please enter a year");
      scanf("%d",&ch);
      if(ch%100!=0)
        if(ch%4==0)
          printf("%d is a leap year\n",ch);
        else
          printf("%d is not a leap year\n",ch);
      else
        printf("%d is a leap year\n",ch);
      getch();
}

我用C写的  编译了 可以用

1999的        if((ch%4==0&&ch%100!=0)||(ch%400==0))

我想:改为
if((ch%400==0||ch%4==0)&&（ch%100））更好些

#include "stdio.h"
#include "conio.h"
void main()
{int ch;
printf("Please enter a year:");
scanf("%d",&ch);
if((ch%4==0&&ch%100!=0)||(ch%400==0))
printf("%d is a leap year\n",ch);
else
printf("%d is not a leap year",ch);
getch();
}


printf那里的 &地址符号去掉

后边缺一个}