#include <iostream>

void toUpper( char array[] ); //or *array

int main()
{
    using std::cout;
    using std::endl;

    char array[6] = "Hello"; //by default it should append the null since I used double
    //quoteswhich indicates it is a string and is not an ordinary array
    
    toUpper( array );

    cout << array << endl;
}

void toUpper( char array[] )
{
    for( int i = 0; array[i]; ++i )
        array[i] = toupper(array[i]); //http://w...content-available-to-author-only...s.com/reference/cctype/toupper/?kw=toupper
}