C Program to check if a input number is a prime number or not

Problem

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

How to find if a number is a prime number in C ?

A Prime Number is a number that is divisible by 1 and by itself. Some of the examples of the prime number are 2 , 3 , 5 etc.

Here’s a program in C demonstrating how to find whether the given number is a prime number or not.

#include <stdio.h>
int main()
{
    int input, index;
    int flag=0;
    printf("Abundantcode.com coding sample \n");
    
    printf("Enter a number : ");
    scanf("%d",&input);

    for(index=2; index<=input/2; ++index)
    {
        if(input%index==0)
        {
            flag=1;
            break;
        }
    }

    if (flag==0)
        printf("%d is a prime number.",input);
    else
        printf("%d is not a prime number.",input);
    
    return 0;
}

C
​x
 
#include <stdio.h>
int main()
{
    int input, index;
    int flag=0;
    printf("Abundantcode.com coding sample \n");
    
    printf("Enter a number : ");
    scanf("%d",&input);
​
    for(index=2; index<=input/2; ++index)
    {
        if(input%index==0)
        {
            flag=1;
            break;
        }
    }
​
    if (flag==0)
        printf("%d is a prime number.",input);
    else
        printf("%d is not a prime number.",input);
    
    return 0;
}

Output

Abundantcode.com coding sample
Enter a number : 7

7 is a prime number.

Tags : C# programs, How to, tutorials

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C Program to check if a input number is a prime number or not

Problem

How to find if a number is a prime number in C ?

Output

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C Program to check if a input number is a prime number or not

Problem

How to find if a number is a prime number in C ?

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