C Program To Find If Two Numbers are Co-Prime or Not using Function

Lets write a C program to check whether two positive numbers entered by the user are Co-Prime numbers / Relative Prime Numbers or not using function / method.

Co-Prime numbers / Relative Prime Numbers: Two numbers are said to be co-prime or relative prime numbers if they do not have a common factor other than 1.

OR

Two numbers whose Greatest Common Divisor(GCD) is 1 are known as Co-Prime or Relative Prime Numbers.

Factors of a number: All the numbers which perfectly divide a given number are called as Factors of that number.

Note: User entered numbers(to check for co-prime) do not require to be prime numbers.

Logic To Find If Two Numbers are Co-Prime or Not

Complete logic is present in our previous day video tutorial, please watch it before continuing: C Program To Find Two Numbers are Co-Prime or Not

Related Read:
C Program To Find Prime Number or Not using While Loop
C Program to Find Factors of a Number using For Loop
Biggest of Two Numbers Using Ternary Operator: C
C Program to Find GCD or HCF of Two Numbers

Video Tutorial: C Program To Find If Two Numbers are Co-Prime or Not using Function

Source Code: C Program To Find If Two Numbers are Co-Prime or Not using Function

#include<stdio.h>

int coprime(int num1, int num2)
{
    int min, count, flag = 1;

    min = num1 < num2 ? num1 : num2;

    for(count = 2; count <= min; count++)
    {
        if( num1 % count == 0 && num2 % count == 0 )
        {
            flag = 0;
            break;
        }
    }

    return(flag);
}

int main()
{
    int n1, n2;

    printf("Enter 2 positive numbers\n");
    scanf("%d%d", &n1, &n2);

    if( coprime(n1, n2) )
    {
        printf("%d and %d are co-prime numbers.\n", n1, n2);
    }
    else
    {
        printf("%d and %d are not co-prime numbers.\n", n1, n2);
    }

    return 0;
}

Output 1:
Enter 2 positive numbers
8
15
8 and 15 are co-prime numbers.

Output 2:
Enter 2 positive numbers
12
15
12 and 15 are not co-prime numbers.

Note:
coprime() method returns 1 or 0 value. If it returns 1, then the code inside if block gets executed. If it returns 0, then the code inside else block gets executed.

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