a c program for prime determination

#include<stdio.h>
#include<conio.h>




main(){
       int i,j,num;
      
       printf("enter a number:");  
       scanf("%d",&num);
      
       for(i=2;i<=num/2;i++){
                             if(num%i==0){
                                          printf("not a prime number");
                                          goto skip;
                                          }
                                         
                            
                             }
       printf("prime number");
      
       skip:                                             
                          
      getch();
      }