Thread: My calculator in Dividing seems wrong I think

Code:

#include <stdio.h>


int main () {
    char a;
    printf("Enter 'M' for Multiplication 'D' for Division and 'A' for Addition and 'S' for Subtraction: ");
    scanf("%c", &a);
    int num1, num2;
    printf("Enter first integer: ");
    scanf("%d", &num1);
    printf("Enter second integer: ");
    scanf("%d", &num2);
    int prod, quo, sum, diff;
    switch (a) {
        case 'M':
            prod = num1*num2;
            printf("%d * %d = ", num1,num2);
            printf("%d", prod);
            break;
        case 'D':
            num2;
            if (num2 == 0)
            printf("Error can't divide\n");
            else
            quo = num1/num2;
            printf ("%d / %d = ", num1, num2);
            printf("%d", quo);
            break;
        case 'A':
            sum = num1+num2;
            printf("%d + %d = ", num1, num2);
            printf("%d", sum);
            break;
        case 'S':
            diff = num1-num2;
            printf("%d - %d = ", num1, num2);
            printf("%d", diff);
            break;
        default:
            printf("Error invalid all words that are synonym to the first two words of this sentence");
        break;
    }
}

When I try going to Divide and I enter my first integer any above 0 and I type 0 in the 2nd integer it will still print what it says in the 'if' statement and still prints what it does in 'else'. What I want to happen is when 'num2 = 0' it will just prints that it will not divide it will just be undefined and it will just terminate without printing '12 / 0 = 0' I mean that is just wrong. Why does it still go on printing?

--New member here please correct me if I've done wrong in the forum rules thanks.--

EDIT: Also in dividing I want to get the remainder of it if possible. How to do that?
EDIT #2: OH found the remainder thingy. Just need to put an integer variable that is equal to 'num1%num2' (remainder = num1%num2) and put it in CASE D. But must be after the quo=num1/num2 and before the printing of the remainder value.

EDIT #3: For some reason my calculator (program) just crashes when I type 0 in the 2nd integer. BUt there are times it wont crash.

Originally Posted by Matticus

Well, let's look at your code for case 'D':

Code:

if (num2 == 0)
printf("Error can't divide\n");
else
quo = num1/num2;
printf ("%d / %d = ", num1, num2);
printf("%d", quo);

Now let's apply some indentation, for us to help see the flow of logic:

Code:

if (num2 == 0)
    printf("Error can't divide\n");
else
    quo = num1/num2;

printf ("%d / %d = ", num1, num2);
printf("%d", quo);

There's the problem. Only a single statement (or block) is executed after an "if" or "else".

If you want a series of statements to be executed, they must be within a block:

Code:

if (num2 == 0)
{
    printf("Error can't divide\n");
}
else
{
    quo = num1/num2;
    printf ("%d / %d = ", num1, num2);
    printf("%d", quo);
}

Welcome to the forum, then. You've done quite well for a first post ... a clear question, using code tags, and a decent (albeit incomplete) attempt at indentation.



Is this before or after the modifications you've implied (adding the modulus operator, or '%')?

I assume it's after, as you might be using the modulus operator with the second number being a zero since the code after "else" is not isolated to that "else" as I've already explained.

Oh yeah Now I see. ) Thanks. But it still crashes damn. Can you recommend me a good compiler? I'm using Dev C++ since it is somewhat useful I can use C++ and C language in one program.

Yeah I tried to use my best english to ask a question here. Haha, forgive my newbie indentions since I am new to programming and I try to indent it as clear as possible for me to read and if possible to other readers.

Also the last question what do you mean? XD Are you talking about the remainder? My code was like this after the block you showed me and I learned from you.

Code:

        num2;
            if (num2 == 0) {
                printf("Error can't divide\n");
            }
            else {
                quo = num1/num2;
                remainder=num1%num2;
                printf ("%d / %d = ", num1, num2);
                printf("%d", quo);
                printf("\nRemainder: %d", remainder);
            }    
            break;

Almost forgot. I declared remainder as an integer equal to num1%num2 first. (int remainder=num1%num2)