c calculator

here's a simple c calculator:

Code:

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

int main()
{
	double num1, num2, result;
	char operator;

	clrscr();

	printf("Enter two numbers and an operator in this form: \n");
	printf("<number1> <operator> <number2> (e.g. 7 + 4) \n");

	scanf("%lf %c %lf", &num1, &operator, &num2);

	if (operator == '+') {
	result = num1 + num2;
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	}
	else if (operator == '-' ) {
	result = num1 - num2;
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	}
	else if (operator == '*' ) {
	result = num1 * num2;
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	}
	else if (operator == '/' ) {
	result = num1 / num2;
	if (num1||num2 == 0) printf("Cannot divide with zero!");
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	} else
	printf("Invalid operator used.");

	return 0;
}

...but i have some problems with it.. can any1 please help me?

...i wanna use the switch() statement instead of using if's and else if's, but i don't know much about it...

...also, i want this program to run in an infinite loop (...while(1) or for(;...), until the user presses a hot-key.. like Ctrl-Q or Alt-X... but, sadly, i dnt also know how... srry..

..thanks in advance for your help... i'll appreciate them for sure... hehehe... -_+

...i wanna use the switch() statement instead of using if's and else if's, but i don't know much about it...

There is a C tutorial available on switch case.

Code:

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

int main()
{
	double num1, num2, result;
	char operator;

	clrscr();

	printf("Enter two numbers and an operator in this form: \n");
	printf("<number1> <operator> <number2> (e.g. 7 + 4) \n");

	while((scanf("%lf %c %lf", &num1, &operator, &num2)) != -1)
{
	switch(operator)
	{
    case '+':
    {
	result = num1 + num2;
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	break;
	}
	case '-':
    {
	result = num1 - num2;
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	break;
	}
	case '*':
    {
	result = num1 * num2;
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	break;
	}
	case  '/':
    {
	result = num1 / num2;
	if (num1 == 0||num2 == 0) printf("Cannot divide with zero!");
	printf("%g %c %g = %g\n", num1, operator, num2, result);
	break;
	} 
    default:
    {
	printf("Invalid operator used.");
	break;
}
}
}
return 0;
}

control + z on windows or control + d on UNIX would stop the loop and end the program.

..ok,, thank you very much for the help..

i tried what you've said, and it worked.. thanks..


..one more question about this program please.... ^.^

Code:

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

int main()
{
    double num1, num2, result;
	char operator;

	while(1)
	{
		clrscr();

		printf("SF7-CaLc by SeViLLa [aka:SF7]");
		printf("\n\nEnter two numbers and an operator in this form: \n");
		printf("<number1> <operator> <number2> (e.g. 7 + 4) \n");
		printf("\n\nEnter here: ");

		scanf("%lf %c %lf", &num1, &operator, &num2);

		switch(operator)
		{
			case '+':
			{
			result = num1 + num2;
			printf("\nOutput: %g %c %g = %g\n", num1, operator, num2, result);
			getch();
			break;
			}

			case '-':
			{
			result = num1 - num2;
			printf("\nOutput: %g %c %g = %g\n", num1, operator, num2, result);
			getch();
			break;
			}

			case '*':
			{
			result = num1 * num2;
			printf("\nOutput: %g %c %g = %g\n", num1, operator, num2, result);
			getch();
			break;
			}

			case  '/':
			{
			result = num1 / num2;
			printf("\nOutput: %g %c %g = %g\n", num1, operator, num2, result);
			getch();
			break;
			}

			default:
			{
			printf("\nInvalid operator used.");
			getch();
			break;
			}

		}
	}

	return 0;
}

...i want the program to exit using Alt+X ...is it possible for me to do that? if yes, please tell me how.... if you can post tutorials/help/tips regarding of the use of hot-keys in c, i would really appreciate it... thanks again... ^.^