#include <stdio.h>
#include <math.h>
main()
{
    int a,b,i,j=0,k,m,n;
    printf("please input two numbles:");
    scanf("%d%d",&a,&b);
    if(a<5||b<=a)
        printf("please input again");
    for(i=a;i<=b;i++)
    {
        m=i;
        while(i>0)
        {
            j=i%10+j*10;
            i=i/10;
        }
        if(m==j)
        {
            for(k=2;k<=sqrt(m);k++)
            {
                n=m%k;
                if(n==0)    goto end;
            }
            printf("%d",m);
        }
        end:k=0;
    }
}

大家帮帮忙吗？我想了好久也没想明白。不要没一个人回答。

#include <stdio.h>
#include <math.h>
#include <string.h>
int isPrime(int n)
{
     int i;
    for(i = 3; i*i <= n; i += 2)
        if(n%i == 0) return 0;
    return 1;
}
main(void)
{
    int a,b,i,j=0,k,m,n;
     char str[10];
    printf("please input two numbles:");
    scanf("%d%d",&a,&b);
    if(a<5||b<=a)
        printf("please input again");
    for(i=a;i<=b;i++)
          {

            m=i;
            sprintf(str,"%d",i);
            if(i%2==0)
            {
                continue;   
            }
            else if(i!=11&&strlen(str)%2==0)
            {
                continue;
            }
            else
            {
                if(!isPrime(i))
                {
                    continue;
                }
                else
                {
                    switch(strlen(str))
                       {
                        case 1:
                                j=i;
                            break;
                        case 3:
                                j=i/100+(i/10%10)*10+(i%10)*100;
                            break;
                        case 5:
                                j=i/10000+(i/1000%10)*10+(i/100%10)*100+(i/10%10)*1000+(i%10)*10000;
                            break;
                        default:
                            if(i==11)j=i;
                            break;
                    };
                }
                if(j==m)
                {
                    printf("%d\n",i);
                }
            }
            }
}

这个函数并没有再次输入的机会阿，再说m＝＝j也不成立阿

我用到这个程序，是对的，但我最想知道的是我的到底错哪了

你这种方法是我以前用的，长而且运行慢，但可行