c - malloc - invalid conversion from void* to double*

Question

I want to write a function that creates a copy of a double array using pointers. This is my code so far:

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

double* copy (double *array, int size)
{
    double *v=malloc(sizeof(double)*size);
    for (int i=0; i<size; i++)
        *(v+i)=*(array+i);
    return v;
}

int main ()
{
    //double array[];
    int size;
    printf ("size= "); scanf ("%i",&size);
    double *array=malloc(sizeof(double)*size);
    for (int i=0; i<size; i++)
        scanf("%f",&array[i]);
    copy(array,size);
    free(array);
}

I have 2 compilation errors that I can't get rid of. I get

invalid conversion from void* to double*

when I try to allocate memory using malloc but I can't understand what I'm doing wrong.

Answer 1

You are using a C++ compiler.

double *array=malloc(sizeof(double)*size);

is valid in C. There is an implicit conversion from any object pointer type to void *.

In C++ it is not valid, there is no such implicit conversion, and you need a cast:

double *array= (double *) malloc(sizeof(double)*size);