How can i fix this problem of " incompatible types"?

How can i fix this problem of " incompatible types"?

Problem Description:

I want to make a program that returns the average of the numbers entered but i get this error:
incompatible types when assigning to type ‘float *’ from type ‘float’

#include <stdio.h>
#include <stdlib.h>
#define CANT ((int)99)
float* promedio (float *dataPtr, int dataCant)
{
float *p;
int a;
float total;

  for ( a = dataCant; a >= 0; a--) {
    total += *dataPtr;
    *dataPtr +=1;
  }
  p = total / dataCant;
  return (p);
}

int main (void)
{
float v[CANT],*q;
int i;

printf ("Ingrese numeros para calcular el promediorn");
printf ("Use -1 para ver el promediorn");
while ((i < CANT) || (v [i] != -1)) {
  printf(" Ingrese un numero: r n");
  scanf ("%f", &v[i]);
  i++;
}
q = promedio (&v[0], i);

printf ("El promedio vale %frn", *q);

free (v);
return (0);
}

Solution – 1

Your approach of returning a pointer from promedio doesn’t make much sens.

You probably want this:

void promedio (float *dataPtr, int dataCant, float *result)
{
  int a;
  float total;

  for ( a = dataCant; a >= 0; a--) {
    total += *dataPtr;
    dataPtr +=1;    // remove the *, you want to increment the pointer
  }                 // not the thing it points to

  *result = total / dataCant;
}

int main (void)
{
  float v[CANT],*q;
  int i;

  printf ("Ingrese numeros para calcular el promediorn");
  printf ("Use -1 para ver el promediorn");

  while ((i < CANT) || (v [i] != -1)) {
    printf(" Ingrese un numero: r n");
    scanf ("%f", &v[i]);
    i++;
  }

  float q;
  promedio (&v[0], i);  // you should write `v` innstead of the cumbersome `&v[0]`

  printf ("El promedio vale %frn", q); // q is a float, removge the *

  // remove free (v), you can only free stuff allocated via malloc and friends
  return (0);
}

Anyway, I have the strong impression you should read again the chapter dealing with pointers in your learning material.

It turns out you rather need this:

float promedio (float *dataPtr, int dataCant)
{
  int a;
  float total;

  for ( a = dataCant; a >= 0; a--) {
    total += *dataPtr;
    dataPtr +=1;    // remove the *, you want to increment the pointer
  }                 // not the thing it points to

  return = total / dataCant;
}

Solution – 2

@Jabberwocky
Thank you for your answer, thanks it I managed to solve the exercise. This is the answer (works)

#include <stdio.h>
#include <stdlib.h>
#define CANT ((int)99)
float promedio (float *dataPtr, int dataCant)
{
  int a;
  float total;

  for ( a = dataCant; a >= 0; a--) {
    total += *dataPtr;
    dataPtr +=1;   
  }

  return (total / dataCant);
}

int main (void)
{
  float v[CANT], q, a;
  int i=0;

  printf ("Ingrese numeros para calcular el promediorn");
  printf ("Use -1 para ver el promediorn");

  while ((i < CANT) && (a != -1)) {
    printf(" Ingrese un numero: r n");
    scanf ("%f", &a);

    if (a != -1) {
      v[i]=a;
      i++;
    }
  }

  q = promedio (&v[0], i);

  printf ("El promedio vale %0.2frn", q);

  return (0);
}