#include <stdio.h>
#include <conio.h>
#include <bios.h>

int main(void)                         /*求P以内的素数*/
{
    unsigned int key;
    unsigned char key1;
    long int i=0,a,p,m,r;
    clrscr();
    printf("\ninput a number p:");
    scanf("%ld",&p);
    for(m=2;m<=p;m++)
    {                                 /*m作为分子也既是被除数*/
        if(kbhit())     /*检查是否按下了键*/
        {
            key = bioskey(0);
            if(key == 283)break;
        }
        r=1;
        for(a=2;a<m;a++)
        if(m%a==0) r=0;
        if(r)
        {
            printf("%5ld",m);
            i++;
            if(i%12==0) printf("\n");
        }
    }
    getch();
    return 0;
}