Thread: Why this prog crashes?

tconverter.c

Code:

#include <stdio.h>
int choice;

float cels(float x);
float fahr(float x);
float kelv(float x);
int main()
{
	float in, out;
	
	while (true){
	in = out = 0;
	choice = 0;
	printf("Wich type of c0nversions do you want to make?\n");
	
	/* The Choice function */
	printf("1)Celsius -> Fahrenheit\n");
	printf("2)Celsius -> Kelvin\n");
	printf("3)Fahrenheit -> Celsius\n");
	printf("4)Fahrenheit -> Kelvin\n");
	printf("5)Kelvin -> Celsius\n");
	printf("6)Kelvin -> Fahrenheit\n");
	
	scanf("%d", choice);
	printf("Value: ");
	scanf("%f", in);
	
	switch (choice) {
		case 1:
			out = cels(in);
			break;
		case 2:
			out = cels(in);
			break;
		case 3:
			out = fahr(in);
			break;
		case 4:
			out = fahr(in);
			break;
		case 5:
			out = kelv(in);
			break;
		case 6:
			out = kelv(in);
			break;
	}
	
	printf("Output: %f\n", out);
	}
}

float cels(float x)
{
	float f, k;
	
	if (choice == 1){
		f = x * 1,8 + 32;
		return f;
	}
	if (choice == 2){
		k = x + 273.15;
		return k;
	}
}

float fahr(float x)
{
	float c, k;
	
	if (choice == 3){
		c = (x - 32) / 1.8;
		return c;
	}
	if (choice == 4){
		k = (x + 459.67) / 1.8;
		return k;
	}
}

float kelv(float x)
{
	float c, f;
	
	if (choice == 5){
		c = x - 273.15;
		return x;
	}
	if (choice == 6){
		f = x * 1.8 - 459.67;
		return f;
	}
}

When I run this prog, it crashes by the first input, why? (BTW, my first serious prog

Code:

scanf("%d", choice);

The second argument to scanf requires an address. You get the address of the variable by using the address-of operator, &.

Thanks mate, didn't see it.