Menu driven program

//Menu driven program 
#include<stdio.h>
#include<stdlib.h>

int main()
{
    int choice,num,i,fact;
    while(1)
    {
        //Display the menu options
        printf("\n1.Factorial\n");
        printf("2.Prime\n");
        printf("3.Odd/Even\n");
        printf("4.Exit\n");
        printf("Your Choice? ");
        
        //Read the user's choice
        scanf("%d",&choice);
        
        //Validate the user's choice
        if(choice < 1 || choice > 4)
        {
            printf("Wrong choice!\a\n");
            continue; //go back to the beginning of the loop
        }
        
        //Exit the program if the user chooses 4
        if(choice == 4)
        {
            exit(0);
        }
        
        //Ask the user to enter a number
        printf("\nEnter number: ");
        scanf("%d",&num);
        
        //Validate the user's number
        if(num < 0)
        {
            printf("Invalid number!\n");
            continue; //go back to the beginning of the loop
        }
        
        //Perform the corresponding operation based on the user's choice
        switch(choice)
        {
            case 1: //Factorial
                fact = 1;
                for(i = 1; i <= num; i++)
                {
                    fact = fact * i;
                }
                printf("Factorial value = %d\n",fact);  
                break;
                
            case 2: //Prime
                for(i = 2; i < num; i++)
                {
                    if(num % i == 0) 
                    {
                        printf("Not a prime number\n"); 
                        break;
                    }
                }
                if(i == num)
                {
                    printf("Prime number\n");
                }
                break;
                
            case 3: //Odd/Even
                if(num % 2 == 0)
                {
                    printf("Even number\n");
                }
                else
                {
                    printf("Odd number\n");
                }
                break;
                
            default:
                //This should never happen
                printf("Something went wrong!\n");          
                
        }
    }
    return 0;
}