/*
 * lt1e.c Laboratory test I for students working on even number machines.
 */
#include <stdio.h>
#define TRUE 1
#define FALSE 0
float pow1p5(float);
int main()
{
    int n, m, absN, sum, prime, i;

// Task 1
    printf("Enter an integer: ");
    scanf("%d", &n);
    if(n%19 == 0) m = n;
    else if (n < 0) m = n/19*19;
         else m = (n + 19) - n%19; 
    printf("\nm: %d \n", m);

// Task 2
    sum = 0;
    absN = (n < 0)? -n:n;
    while(absN){
          sum = sum + absN % 10;
          absN = absN / 10;
    }
    printf("Sum of digits of %d = %d\n", n, sum);
   
// Task 3
    absN = (n < 0)? -n:n;
    if(absN == 0 || absN == 1) 
          printf("2 is the smallest prime >= |%d|\n", n);
    else {
          while(1){
             prime = TRUE;
             for(i=2; i<=absN/2; ++i){
                 if(absN%i == 0){
                    prime = FALSE;
                    break;
                 } 
             }
             if(prime) break;
             else absN = absN + 1;
          } 
          printf("%d is the smalest prime >= |%d|\n", absN, n);
    }    

// Task 4
    printf("|%d|^1.5 = %f\n", n, pow1p5((n < 0)?-n:n)); 
    return 0;
}
float pow1p5(float x){
      float x0, x1, err, x1Abs ;

      if(x == 0.0) return 0.0;
      x0 = x/2;
      do {
          x1 = x0 - (x0*x0 - x)/2.0/x0;
          err = x1 - x0;
          err = (err < 0)? -err: err;
          x1Abs = (x1 < 0)? -x1: x1; 
          x0 = x1;
      } while(err > 0.0001*x1Abs/100.00);
      return x*x1;
}