Question

1) Write a C program to print the prime numbers from 1 to 100. (A prime integer is any integer that can be divided evenly only by itself and 1)

Requirement: Use an array to take the number from 1 to 100 and another array to take the prime number.

Answer 1

Please follow the code and comments for description :

CODE :

/* C program to find all prime numbers from the inputted array */
#include<stdio.h>

int main() // driver method
{
   int ar[100], i, n, j, counter, res[100], m = 0; // local variables
  
   for(i = 0; i < 100; i++) // iterate and save the data
   {
       ar[i] = (i + 1);
   }
  
   printf("The Array is - \n"); // message
   for(i = 0; i < 100; i++)
   {
       printf("\t %d", ar[i]); // message
   }
  
   printf("\n");
   printf("\nAll the Prime Numbers in the Array are -\n"); // message
   for(i = 0; i < 100; i++) // iterate to calcualte the primes
   {
       counter = 0;
       for(j = 2; j < ar[i]; j++)
       {
           if(ar[i] % j == 0) // prime number condition
           {
               counter = 1;
               break;
           }
       }
       if(counter == 0) // if true
       {
            res[m] = ar[i]; // assign to another array
           printf("\t %d", res[m]); // message
           m++; // increment the count
       }
   }
   printf("\n"); // new line character
   return 0;
}

OUTPUT :

Hope this is helpful.