void panding( int a,int b )
{
        int flag=0;
        int r,i,j;
        if( a>b )
        {
                r=a;
                a=b;
                b=r;
        }
        for(i=a;i<=b;i++)
        {
                for(j=2;j<i;j++)
                {
                        if(i%j==0){
                        //      printf("not sushu");
                                flag=1;
                                break;
                        }
                }
                if(flag==0){
                                printf("%d is sushu\n",i);

                }
        }
}


void shuru(int a[])
{
    scanf("%d,%d",&a[0],&a[1]);
}

void main()
{
        int shuzu[2]={0};
        int jieguo[100]={0};
        shuru(shuzu);
        printf("the number you input is:%d,%d\n",shuzu[0],shuzu[1]);
        panding(shuzu[0],shuzu[1]);

}

//输入两个数，求两个数之间的所有素数
#include <stdio.h>
void panding( int a,int b )
{
        int flag=0;
        int r,i,j;
        if( a>b )
        {
                r=a;
                a=b;
                b=r;
        }
        for(i=a;i<=b;i++)
        {
                flag=0;                //----- 必须对每个数，首先令flag=0
                for(j=2;j<i;j++)
                {
                        if(i%j==0){
                        //      printf("not sushu");
                                flag=1;
                                break;
                        }
                }
                if(flag==0){
                               // printf("%d is sushu\n",i);
                                printf("%5d",i);         //-----这样好看一点

                }
        }
}


void shuru(int a[])
{
    scanf("%d,%d",&a[0],&a[1]);
}

void main()
{
        int shuzu[2]={0};
        int jieguo[100]={0};
        shuru(shuzu);
        printf("the number you input is:%d,%d\n",shuzu[0],shuzu[1]);
        panding(shuzu[0],shuzu[1]);
        printf("\n");

}

[ 本帖最后由 ying8501 于 2014-3-10 12:14 编辑 ]

break不是强制性结束循环的么？

break只是退出它所属的单层循环！

楼主看明白了吗？实际上，只是循环内少了flag=0。