Time past Midnight in seconds (C++)

/*
@Project: Write a program that uses a function that tasks 3 arguments
of time(hours, minutes, and seconds). The function will take those parameters,
calculate, and display the # of seconds that have elapsed since midnight.
The program should allow the user to enter in the arguments.
@Author: BaSs_HaXoR
@Date: 02/04/15
@Class: Intro to C++ Programming
*/

#include <iostream>

using namespace std;

const int MIDNIGHT = 12;
const int MAXSEC = 60;
const int MAXMIN = 60;
int Hours;
int Minutes;
int Seconds;

void _checkHours(int hours)
{
    if(hours >= 24)
    {
        Hours = hours % 12;
    }
    else
    {
        Hours = hours;
    }
}

void _checkMinutes(int minutes)
{
    if(minutes >= MAXMIN)
    {
        Minutes = minutes % 60;
    }
    else
    {
        Minutes = minutes;
    }
}

void _checkSeconds(int seconds)
{
    if(seconds >= MAXSEC)
    {
        Seconds = seconds % 60;
    }
    else
    {
        Seconds = seconds;
    }
}

int _returnSeconds()
{
    int output;
    output = Hours * MAXSEC * MAXMIN;
    output = output + (Minutes * MAXMIN);
    output = output + Seconds;
    return output;
}
void _sinceMidnight(int hours, int minutes, int seconds)
{
    _checkHours(hours);
    _checkMinutes(minutes);
    _checkSeconds(seconds);
}

int main(int args, char *argv[])
{
    cout<<"Please enter hours: ";
    cin >> Hours;
    cout<<"Please enter minutes: ";
    cin >> Minutes;
    cout<<"Please enter seconds: ";
    cin >> Seconds;

    _sinceMidnight(Hours, Minutes, Seconds);
    cout<<"Time past Midnight: "<<Hours<<" hours, "<<Minutes<<" minutes, "<<Seconds<<" seconds."<<endl;
    cout<<"Time past Midnight (In Seconds): "<< _returnSeconds()<<endl;
    cin.get();

}
//BaSs_HaXoR