程序代码：

root@~ #cat 713.c
#include <stdio.h>

int main (void) {

        int isp (int num);
        int i,n,count=0;

        printf("Enter digit :");
        scanf("%i",&n);

        for(i=1;i<=n;i++) {
                if(isp(i)==1) {
                        printf ("%i\n",i);
                        count++;
                }
        }

        printf("Numbers of prime is :%i\n",count);

        return 0;

}
int isp (int num) {
        int i;
        for (i=num-1;i>1;i--) {
                if (num%i==0) {
                        return 0;
                        break;
                }
        }
        return 1;
}
root@~ #./713
Enter digit :10
1
2
3
5
7
Numbers of prime is :5
root@~ #