Some C ideas

important.c

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
// function to check if the number entered is prime or not
int prime(int b)
{int i,truth = 1;
    for(i = 2;i<(b/2);i++)
    {
      if(b%i == 0)
      {   truth = 0;
          break;
      }
    }
    if (truth)
        return 1;
    else
        return 0;
     
}
// function to print an array
void printArray(int A[], int size)
{
int i;
for (i=0; i < size; i++)
printf("%d ", A[i]);
printf("\n");
}

// function to print a 2d array
void print2d(int arr[100][100],int l,int h)
{
    int i, j;
     for (int i = 0; i < l; i++) {
           for (int j = 0; j < h; j++) {
               printf("%d ",arr[i][j]);
           }
           printf("\n");
       }
}

int main(void) {
    int f;
    scanf("%d",&f);
    f = prime(f);
   if(f)
       printf("Prime");
    else
        printf("Not");
    return 0;
 }