#include "stdio.h"
#include "math.h"
void main()
{
    int k,i;
    k=1;
    int sushu(int x);
    for(i=100;i<=200;i++,k++)
       {
            if(k%10==0)
            printf("\n");
         sushu(i);
       }
}
  void sushu(int x)
  {
      int n,j;
      n=sqrt(x);
      for(j=2;j<=n;j++)
         {
               if(x%j==0)
                 break;
         }
       if(j>n)
         printf("a prime number");
       else
         printf("not a prime number");
  }

  改了，lx的~也运行不了，不知道怎么搞~

[ 本帖最后由 kidundead 于 2009-10-17 17:13 编辑 ]

你想说的是哪错了?

#include "stdio.h"
#include "math.h"
void main()
{
    int k,i;
    k=1;
    void sushu(int x); //你定义与下面的函数的类型不一样,可改成VOID
    for(i=100;i<=200;i++,k++)
       {
            if(k%10==0)
            printf("\n");
         sushu(i);
       }
}
  void sushu(int x)
  {
      int n,j;
      n=(int)sqrt(x); //将这里强制转换成整型
      for(j=2;j<=n;j++)
         {
               if(x%j==0)
                 break;
         }
       if(j>n)
         printf("a prime number");
       else
         printf("not a prime number");
  }

楼上程序运行结果
not a prime numbera prime numbernot a prime numbera prime numbernot a prime numb
ernot a prime numbernot a prime numbera prime numbernot a prime number
a prime numbernot a prime numbernot a prime numbernot a prime numbera prime numb
ernot a prime numbernot a prime numbernot a prime numbernot a prime numbernot a
prime number
not a prime numbernot a prime numbernot a prime numbernot a prime numbernot a pr
ime numbernot a prime numbernot a prime numbernot a prime numbera prime numberno
t a prime number
not a prime numbernot a prime numbera prime numbernot a prime numbernot a prime
numbernot a prime numbernot a prime numbernot a prime numbera prime numbernot a
prime number
a prime numbernot a prime numbernot a prime numbernot a prime numbernot a prime
numbernot a prime numbernot a prime numbernot a prime numbernot a prime numberno
t a prime number
a prime numbernot a prime numbera prime numbernot a prime numbernot a prime numb
ernot a prime numbernot a prime numbernot a prime numbera prime numbernot a prim
e number
not a prime numbernot a prime numbernot a prime numbernot a prime numbera prime
numbernot a prime numbernot a prime numbernot a prime numbera prime numbernot a
prime number
not a prime numbernot a prime numbernot a prime numbernot a prime numbera prime
numbernot a prime numbernot a prime numbernot a prime numbernot a prime numberno
t a prime number
a prime numbernot a prime numbera prime numbernot a prime numbernot a prime numb
ernot a prime numbernot a prime numbernot a prime numbernot a prime numbernot a
prime number
not a prime numbernot a prime numbera prime numbernot a prime numbera prime numb
ernot a prime numbernot a prime numbernot a prime numbera prime numbernot a prim
e number
a prime numbernot a prime numberPress any key to continue
出现错误！

#include "stdio.h"  
#include "math.h"  
#include<conio.h>
void main()  
{     void sushu(int x); //声明应该该写在这里
    int k,i;  
    k=1;  
 
    for(i=100;i<=200;i++,k++)  
       {  
            if(k%10==0)  
            printf("\n");  
         sushu(i);  
       }  
       getch();
   }
  void sushu(int x)  
  {  
      int n,j;  
      n=(int)sqrt(x);
      for(j=2;j<=n;j++)  
         {  
               if(x%j==0)  
                 printf("%d ",x);
         }  
    /*   if(j>n)
         printf("a prime number");  
       else  
         printf("not a prime number");  */
 
  } 这样还行。

试试这个。
#include "stdio.h"
#include "math.h"
void main()
{
    int k,i;
    k=1;
    void sushu(int x);
    for(i=100;i<=200;i++,k++)
       {
            if(k%10==0)
            printf("\n");
         sushu(i);
       }
}
  void sushu(int x)
  {
      int n,j;
      n=sqrt(x);
      for(j=2;j<=n;j++)
         {
               if(x%j==0)
                 break;
         }
       if(j>n)
         printf("%d is a prime number     ",x);
       else
         printf("%d is not a prime number     ",x);
  }