Getting “void* is not a pointer-to-object type” error but the code executes perfectly when using XCode

Question

When executing the following code I get the above mentioned error when function change is executed. I have not used any dereferencing nor have used void* anywhere. At first I thought it was because of (double *) malloc(..) but even upon using static memory allocation the problem still holds. Additionally, compiler says that max_element is not a member of std:: or "error: 'max_element' was not declared in this scope"

#include <iostream>
#include <cmath>
#include <tgmath.h>
#include <vector>
#include <stdio.h>
using namespace std;

struct Exchange{
    int nHalf ;
    int nThird ;
    int nFourht ;
    int amDollars[3] ;
 };
void change (double n, Exchange& a) ;

// Main function for the program
int main( )
{
    int i = 0 ;
    vector <int> n ;
    n.reserve(10) ;
    vector<Exchange>coin ;
    coin.reserve(10) ;
//    n = (double *) malloc(sizeof(double)) ;
    do{
        cin >> n[i] ;
        change (n[i], coin[i]) ;
        coin[i].amDollars[0] =
        coin[i].nHalf + coin[i].nThird + coin[i].nFourht ;
        coin[i].amDollars[1] = n[i] ;
        coin[i].amDollars[2] = 0 ;
        cout << *max_element(&coin[i].amDollars[0], &coin[i].amDollars[2]) << endl ;
        i++ ;
    }while (i < 10) ;

    return 0;
}

void change (double n, Exchange& a) {

    a.nHalf = trunc(n/2) ;
    a.nThird = trunc(n/3) ;
    a.nFourht = trunc(n/4) ;

}

Answer 1

Very likely that first error is produced by tgmath.h . Try to replace it with ctgmath . Or, if you doesn't need to operate with complex numbers, just use cmath .