Returning float in void* function

Question

I'm learning how pointers works, but I don't understand one thing in this code. Returning int in void* function works like a charm, but returning float does'nt.

#include <stdio.h>

void* square (const void* num);

int main() {
  int x, sq_int;
  x = 6;
  sq_int = square(&x);
  printf("%d squared is %d\n", x, sq_int);

  return 0;
}

void* square (const void *num) {
  int result;
  result = (*(int *)num) * (*(int *)num);
  return result;
}

#include <stdio.h>

void* square (const void* num);

int main() {
  float x, sq_int;
  x = 6;
  sq_int = square(&x);
  printf("%f squared is %f\n", x, sq_int);

  return 0;
}

void* square (const void *num) {
  float result;
  result = (*(float *)num) * (*(float *)num);
  return result;
}

Answer 1

If you still want to want this to work, you should return a pointer to a float. But doing this in a function involves some heap allocation. Code could we look like this. I didn't include any checks if there is a real float returned or not. This is your task

#include <stdio.h>
#include <stdlib.h>


void* square (const void* num);

int main() {
  float *x, sq_int;
  float value = 6;
  x = square(&value);
  printf("%f squared is %f\n", value, *x);
  free(x);
  return 0;
}

void* square (const void *num) {
  float *result = malloc(sizeof(float));
  *result = (*(float *)num) * (*(float *)num);
  return ((float*)result);
}