CPP program to find out a number is prime or not using function

Source Code:
#include<iostream>
using namespace std;
void isprime(int n)
{
int i,flag=0,m=0;
m=n/2;
for(i=2;i<=m;i++)
{
if(n%i==0)
{
cout<<"Number is not Prime."<<endl;
flag=1;
break;
}
}
if(flag==0)
  cout<<"Number is Prime"<<endl;
}

int main()
{
int x;
cout<<"Enter a number: ";
cin>>x;
isprime(x);
return 0;
}

Program Output: