try yourself |run program

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

int num; 
void readNum(){ 
 printf("\n Enter Number: "); 
 scanf("%d",&num);
}

void calculation(){ 
  int res;
 res = num % 2;
 if(res == 0){
 printf("\n %d is even number",num);
}
 else{
 printf("\n %d is odd number",num);
  }
}

void main(){
 clrscr();
 readNum();
 calculation();
 getch();
}

Program Output

Enter Number: 10
10 is even number