Thread: Can't quit my program

Hi, I have a problem that involve global variables. Basicaly, i start in a while loop when a value is true but i cant make that value false when in another function.
I have 2 source files and one header file below.
Could some please tell me where to declare "active" to make this work.

main.c

Code:

#include <stdio.h>
#include <math.h>
#include "functions.h"

bool active = true;

int main()
{
	while(active)
	{
		menu();
	}
}

functions.h

Code:

int distance();
void retry();
int quit();
int menu();

lines.c

Code:

#include <stdio.h>
#include <math.h>

struct point2D
{
	float x;
	float y;
}pa,pb;

int distance()
{
	float d;

	printf("\nPlease enter the first point: ");
	scanf("%f" "%f", &pa.x, &pa.y);
	printf("Please enter the second point: ");
	scanf("%f" "%f", &pb.x, &pb.y);

	d = sqrt(pow(pb.x-pa.x,2)+pow(pb.y-pa.y,2));

	printf("The distance between these points is: %f\n\a",d);

	return(0);
}

int quit()
{
	active = false; //THIS IS THE ERROR!! active: undeclared variable
	return(0);
}

int menu()
{
	int choice;
	printf("\n****************Main Menu*******************\n");
	printf("1.Distance between two points\n");
	printf("2.Quit\n");
	printf("********************************************\n");
	printf("Please enter your choice: ");
	scanf("%d", &choice);

	switch(choice)
	{
	case 1:
			  distance();
		break;
	case 2:
			  quit();
		break;
	default:
		//retry();
		break;
	}

	return(0);
}

In your other source file, you can place:

Code:

extern bool active;

The extern keyword just tells the compiler that the active variable is declared somewhere in another file, but to let this file use it also.

Thanks bithub
That is handy
Cheers