Thread: Trouble with program

Hey all, I am having this problem in my intro to programming class. This program will execute correctly but the only answer I get is 0. Can someone help me?

Instructions: Write a program that will convert a dollar amount and return the number of cents in the amount. For example, if the user enters 5.33 then your program should return "533 cents". Your program should use a function (besides the main) called compute_cents that will take the dollar amount entered by the user and return the number of cents in the amount.

code:

Code:

#include <stdio.h>
int compute_cents(int cents);
int main(void)
{
     double dollar_amount, cents;
     printf("Enter dollar amount");
     scanf_s("%lf", &dollar_amount);
     cents = 100 * dollar_amount;
     printf("Cents: %d", cents);
     return 0;
}


int compute_cents(int cents);

In your program as is, you don't need the compute_cents prototypes since you haven't written the function and aren't trying to use it. Note however that you've declared cents in main as a double but are printing it with "%d" which is used for ints. Changing the "%d" to "%f.0" should work.

But the instructions say to use a function.

Originally Posted by algorism

In your program as is, you don't need the compute_cents prototypes since you haven't written the function and aren't trying to use it. Note however that you've declared cents in main as a double but are printing it with "%d" which is used for ints. Changing the "%d" to "%f.0" should work.

But the instructions say to use a function.

That worked! Thank you very much. The only issue is that if I remove the compute_cents prototype it works perfectly. I know that my instructor had a reason for us to use that header so I think that I am doing something wrong.

You're supposed to write a function to go along with that function prototype.
In that case, it will return an int and you should print it with "%d".
Actually, the function prototype looks wrong since it's supposed to take in the dollar_amount and return the cents.
Presumably it should be:

Code:

int compute_cents(double dollar_amount);

Then the function would look something like this:

Code:

int compute_cents(double dollar_amount) {
    int cents;

    // compute the cents (as an int) here

    return cents;
}

And your main would be something like:

Code:

int main(void)
{
    double dollar_amount;
    int cents;

    printf("Enter dollar amount");
    scanf_s("%lf", &dollar_amount);

    cents = compute_cents(dollar_amount);

    printf("Cents: %d\n", cents);

    return 0;
}

Thanks! Unfortunately on the "return cents;" line, it is saying that cents in uninitialized.

Originally Posted by Kosios

Thanks! Unfortunately on the "return cents;" line, it is saying that cents in uninitialized.

Well, duh! It's not the whole program. You need to first of all THINK (jeez!), and then fill in the part where I put a comment. I've given you too much already.

Oh tha'ts what that was... i'm new at this lol. Thanks again!