Stopwatch program in standard C

Question

I'm trying to create a program of a stopwatch using this Standard C-Free 5.0. Here's what I've got so far:

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

char button;
int minutes=0, seconds=0, millisec=0;

int main(void)
{
    while(1)
    {
        reset:
        button = '\0';
        int minutes=0, seconds=0, millisec=0;
        printf("  %d :  %d :  %d ", minutes, seconds, millisec);
        system("cls");
        if(button == 'a')
        {
            while(1)
            {
                cont:
                button = '\0';
                Sleep(10);
                millisec++;
                if(millisec == 100)
                {
                    millisec = 0;
                    seconds++;
                    if(seconds == 60)
                    {
                        seconds = 0;
                        minutes++;
                    }
                }
                printf("  %d :  %d :  %d ", minutes, seconds, millisec);
                system("cls");
                if(button == 's')
                {
                    while(1)
                    {
                        button = '\0';
                        printf("  %d :  %d :  %d ", minutes, seconds, millisec);
                        system("cls");
                        if(button == 'a')
                        {
                            goto cont;
                        }
                        if(button == 'd')
                        {
                            goto reset;
                        }
                    }
                }
            }
        }
    }
}

I'm trying to start the stopwatch with a pressed of button 'a' but it wouldn't work. Using scanf() will pause the whole program. Is there a way to detect a button being pressed and continue the stopwatch program? I mean without pausing the program especially the pressing 's' to stop and pressing 'a' again to continue, while displaying the timer at all times.

Answer 1

This should help _kbhit and it's important to use _getch() after it.

#include <conio.h>

//...

int key;
while (1)
{
    if (_kbhit())
    {
        key = _getch();

        if (key == 'a')
            printf("You pressed 'a'\n");
        else if (key == 'd')
            printf("You pressed 'd'\n");
    }
}