sqrt function causing " 'void*' is not a pointer-to-object type" error

Question

I am working in C++, making a pretty simple function that is supposed to calculate the standard deviation of a given number entered by the user. But when I try to use the sqrt function with my variable mean , there is an error I get when attempting to compile my program:

'void*' is not a pointer-to-object type

Below is my code, as well as a picture of the error message.

#include <iostream>
#include <tgmath.h>
#include "stddev.h" //this is just a seperate header file that I have going with my program

using namespace std;

void stats (float *data, int n){

    float mean = 0;
    int i;

    for (i = 0; i < n; i++){
        mean += data[i];
    }

    mean = mean / n;

    for(i = 0; i < n; i++) { //subtracting the mean from the number and squaring the result.
        data[i] = data[i] - mean;
        data[i] = data[i] * data[i];
    }

    mean = 0;

    for (i = 0; i < n; i++){
        mean += data[i];
    }

    mean = mean / n;

    float stdDeviation = sqrt(mean); //Here is where I get the error

    cout << "\t Your Standard Deviation is : " << stdDeviation << endl;
}

Answer 1

Use of <tgmath.h> (or <ctgmath> ) is deprecated in C++.

It's supposed to still work -- <tgmath.h> is meant to be exactly equivalent to including <cmath> and <complex> -- so you are looking at a compiler/library bug. But perhaps this is something that the vendors are not really interested in putting time into fixing since it is deprecated.

Things should go more smoothly to use #include <cmath> instead of #include <tgmath.h> .