prime number

#include<stdio.h>
#include<math.h>
int main()
{
    int n,i,root,flag=0;
    printf("enter a number: ");
    scanf("%d",&n);
    root=sqrt(n);
    for(i=2;i<=root;i++)
    {
        if(n%i== 0)
        {
            flag = 1;
            break;
        }
        else
        {
            flag=0;
            break;
        }
    }

    if(flag==0)
    {
        printf("%d is a prime number",n);
    }
    else
    {
        printf("%d is not a prime number",n);
    }
    return 0;
}