质数

#include<stdio.h>
#include<math.h>
int main(){
    int n,i;
    double k;
    printf("please input a number:"); 
    scanf("%d", &n);
    if (n<=1){
        printf("This is not a prime\n");
    } else{
        for (i=2;i<=sqrt(n);i++){
            if (n%i==0) break;
        }
        if (i<=sqrt(n)) printf("This is not a prime.\n");
        else printf("This is a prime\n");
    }
    return 0;
}

bool zhishu(int n)//质数判断
{
    if(n==2)
        return true;
    if(n%2==0)
        return false;
    for(int i=3;i<=sqrt(n);i=i+2)
    {
        if(n%i==0)
            return false;
    }
    return true;
}