Prime or Composite number

The coding starts from next line:-

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#include<iostream.h>

#include<conio.h>

#include<math.h>

#include<dos.h>

void main()

{

clrscr();

int i,num,ans;

cout<<"\nEnter the number you want to check:";

cin>>num;

for(i=2;i<=(num-1);i++)          //(i=2;i<=num/2;i++)

{

if(num%2==0)

{

ans=1;

break;

}

else

{

ans=0;

}

}

if(ans==1)

{

cout<<"\It is a composite number";

}

else {

cout<<"\nits a prime number";

}

getch();

}