Question

Use "do...while" loops to write a program that finds all prime numbers less than a specified value.

Answer 1

%Program to find follows

#include <stdio.h>
#include <math.h>

int main(void)
{ printf("Please enter a maximum value...\n"); int max;
    scanf("%d", &max);

    int current = 4;
    int checker = 2;
    do{
        if(checker > sqrt((double)current))
        {
            checker = 2;
            printf("%d is prime\n",current);
            current++;
        }
        else if(current % checker == 0)
        {
            checker = 2;
            printf("%d is NOT prime\n",current);
            current++;
        }
        else
            checker++;
    }while(current < max);
}

Output:

I have entered max value is 20.