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Prime Number Program in C using Function

Write a program in C to check whether a number is a prime number or not using the functions.

#include<stdio.h>

#include<stdbool.h>

bool isPrime(int);

int main()

{

   int n; /*’n’ is user defined number.*/

   printf(“Enter a number :”);

   scanf(“%d”,&n);

   if(isPrime(n)) /*if isPrime() return’s TRUE, then if statement will execute otherwise else will execute*/

      printf(“Given number is PRIME number\n”);

   else

      printf(“Given number is Non-PRIME number\n”);

   return 1;

}

bool isPrime(int n)

{

    int i,count;

    count=0;

    for(i=1;i<=n;i++)

   {

      if(n%i==0) /*check the iteration value is factor of given number or not.*/

         count++;

   }

   if(count==2)

        return 1; /*true & false are defined words from “stdbool.h” we can also use 1 & 0*/

    return 0; /*Here we did not use “else” because when a “return” statement appears Compiler automatically terminates the function and returns the value, so when the if condition fails then only “return 0” will execute*/

}

Output:

i) Enter a number : 7919

Given number is PRIME number

ii)Enter a number : 852

Given number is Non-PRIME number


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Write a C program to generate first ‘n’ prime numbers, where n is a value Supplied by the user.