Question

Write a program in C that asks for an integer n, if n is greater than 100 or if it is less than 1, output an error message. If n is in the range {1, . . . , 100} then if n is either 2,3,5, or 7, output “YES”; or if n is not divisible into 2,3,5 or 7 also output “YES” if n 6= 1; otherwise, output “NO”. Yes, you’re right, a very simple program that checks if a number up to one hundred is prime (implement the program only with if statements)

Answer 1

Thanks for the question,

Here is the complete program in C language using only If condition, not even else of else if

Let me know for any doubts or question.

===========================================================================

#include<stdio.h>

int main(){
  
   int num;
  
   printf("Enter a number between 1 and 100 (both inclusive): ");
   scanf("%d",&num);
  
   if(1<=num && num<=100){
      
       if(num==2 || num==3 || num==5 || num==7 ){
           printf("YES\n");
       }
      
       if(!(num%2==0) && !(num%3==0) && !(num%5==0) && !(num%7==0)) {
           printf("YES\n");
       }
      
       if((num!=2 && num!=3 && num!=5 && num!=7) &&( num) &&(num%2==0 ||
           num%3==0 || num%5==0 || num%7==0
       )){
           printf("NO\n");
       }
      
      
      
   }
  
   if(num<1 || num>100)   {
      
       printf("Error: The number was not between 1 and 100.\n");
   }
}

========================================================================

Answer 2

Code :-

#include <stdio.h>

int main() {

    int n;

    

    // Ask for input

    printf("Enter an integer between 1 and 100: ");

    scanf("%d", &n);

    

    // Check if input is out of range

    if (n < 1 || n > 100) {

        printf("Error: Number must be between 1 and 100.\n");

        return 1;

    }

    

    // Check for prime numbers

    if (n == 2 || n == 3 || n == 5 || n == 7) {

        printf("YES\n");  // Output for primes 2,3,5,7

    } else if (n != 1 && n % 2 != 0 && n % 3 != 0 && n % 5 != 0 && n % 7 != 0) {

        printf("YES\n");  // Output for other primes

    } else {

        printf("NO\n");   // Output for non-primes and 1

    }

    

    return 0;

}

 clude <stdio.h>int main() {