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C Program to check whether a given number is prime or not (using do-while loop)

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A number is said to be prime if it is divisible by 1 and itself. It should not have any other divisors. Check whether a given number is prime or not (using do-while loop)

Program Code

#include<stdio.h>
void main()
{

int number, i = 2;
int indicator =  0;
printf("Enter a number to check prime or Not: ");
scanf("%d",&number);

do{
	if(number%i == 0)
	{
	 indicator = 1;
	 break;
	}
 
 i++;
}while(i < number/2);

if(indicator == 1){
	printf(" \n Number %d is not prime. \n", number);
}
else{
	printf(" \n Number %d is prime. \n", number);
}

}

Output

Enter a number to check prime or Not: 13

 Number 13 is prime. 

Explanation

How to learn from this program

First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.