Need help in storing characters

[843]

Can someone tell me what am I doing wrong? The printed values are not the characters I input. I'm writing the code this way because I'm having trouble returning two values from the info function.

#include <stdio.h>

char info ()
{
    char x;

    printf("Insert a character: ");
    getchar();
    scanf("%c", &x);

    return x;
}

void main ()
{
    char a, b, x;

    info ();
    a = x;
    info ();
    b = x;
    printf("%c and %c", a, b);
}

[claudiu]

Well, you are calling info which returns its value to nowhere as it is discarded, thus you lose everything you read. a,b,x remain uninitialized and may contain any rubbish known to man.

you want to do a = info(), b = info().

HOWEVER, even your info function is wrong.Move the getchar() after your scanf to eat the enter key you press.

Also, main should be int main(void) and should return 0;

[843]

Thanks for the thorough help. The program works without declaring main() as int and adding the return 0 line. Is it necessary? I mean, the main function isn't supposed to return any value...

It's weird that I've always used getchar() before scanf() and the program always worked, but not in this case. For instance:

#include <stdio.h> //standard header

void main()
{
	float celsius, fahrenheit; //variables declared with float to allow for decimal places
	char ans; //required to repeat the loop

	do  //loop start
	{
	printf("Enter temperature in Fahrenheit: ");
	scanf("%f", &fahrenheit); //input in Fahrenheit
	celsius = (fahrenheit - 32) * 5 / 9; //conversion formula
	printf("%.4f Fahrenheit is %.4f Celsius\n", fahrenheit, celsius); //displays output with 4 decimal places

	printf("Do you want to try again? [Y/N]"); //loop prompt
	getchar(); //required for the following scanf to work
	scanf("%c", &ans); //asks if user wants to retry
	} while (ans == 'y' || ans == 'Y'); //condition for loop
}

What makes this input characteristic different?

[claudiu]

No, you are doing the same thing there... You are scanf-ing something... later on in the code you are getchar()-ing which eats the enter key pressed after the first scanf (THAT IS INPUT TOO!), and then you are scanf-ing again. If you remove that getchar() your enter key (i.e. new line ) will be fed into the second scanf which won't even wait for you to input anything. Try it out.

As for main(), main is supposed to return an integer. In older C versions this was done automatically which is why you could write main(). However, since this is the 21st century and we have evolved from C89 quite a bit the correct forms are now:

int main(void){
 /* this program does not take arguments */
 return 0;
}

int main(int argc, char* argv[]){
/* this program takes argc arguments stored in argv */
 return 0;
}

To read more about it go here:
Cprogramming.com FAQ > main() / void main() / int main() / int main(void) / int main(int argc, char *argv[])

[843]

Ah, that explains why the second scanf wouldn't work without the getchar(). So they are always used together to eat up the Enter key? Is this normal?

[claudiu]

If you plan to take input in the way you do (with scanf) then yes, it's pretty normal. There are other ways to take input in C and parse it afterwards. I suggest you look at functions like fgets(), fgetc(), sscanf(), sprintf() to learn more.

[843]

Thanks for the info.