Thread: Just a simple program just confused

Code:

#include <stdio.h>
#include <stdlib.h>


int main()
{
    float totalProfit;
    int priceOfmalunggay;
    int tax;
    int totalMalunggay;


    printf("How many malunggay did you get?\n");
    scanf("%d", &totalMalunggay);
    printf("How much did you sell the Malunggay?\n");
    scanf("%d", &priceOfmalunggay);
    printf("What is the percentage of your value added tax?\n");
    scanf("%d", &tax);
    tax = tax/100;
    totalProfit = ((float)priceOfmalunggay * (float)totalMalunggay) * (float)tax;


    printf("Your total profit is: %.2f", totalProfit);




    return 0;
}

Just want to know why it is 0 everytime.

Because 'tax' is an integer, and in line 19 you divide that integer, which is most likely something < 100, by 100. The result is always 0, making the result of your calculation in line 20 also 0.

Originally Posted by spaghetticode

Because 'tax' is an integer, and in line 19 you divide that integer, which is most likely something < 100, by 100. The result is always 0, making the result of your calculation in line 20 also 0.

What should I put? I changed tax to float still it wont work.

Show your updated code, example input and the according output.

Originally Posted by YaZao

What should I put? I changed tax to float still it wont work.

Make tax and priceOfmalunggay both floats, change scanf() to input both as floats, and you should be OK. Are the tax and price usually integers, or floating point values? As @spaghetticode said, please post your updated code.

Originally Posted by rstanley

change scanf() to input both as floats

Oh sure, I did not think about that one, you're still reading in integers!

Code:

#include #include int main(){    float totalProfit;    int priceOfmalunggay;    float tax;    int totalMalunggay;    printf("How many malunggay did you get?\n");    scanf("%d", &totalMalunggay);    printf("How much did you sell the Malunggay?\n");    scanf("%d", &priceOfmalunggay);    printf("What is the percentage of your value added tax?\n");    scanf("%f", &tax);    tax = tax/100;    totalProfit = ((float)priceOfmalunggay * (float)totalMalunggay) * (float)tax;    printf("Your total profit is: %.2f", totalProfit);    return 0;}

okay what I did is in line 18 I just changed "%d" to "%f" just like you guys were saying. And changed "int tax" to "float tax" and it went well.

Good to hear and good job!

Besides all your code appearing one one line here, you could also drop the casts as you have changed two of the three variables to floats, and the price variable will promote to.floating point in the calculation. Are you sure the price variable should not be floating point?

Originally Posted by rstanley

Are you sure the price variable should not be floating point?

Whenever a program deals with money values, it literally cries for floating point data types. The amount of coins < 1 Euro in my wallet says so, too.

Sure, that was not accurate. What I meant was 'non-integer numeric data types'.

Originally Posted by laserlight

No, it cries for types that can accurately handle money values, e.g., fixed point decimal. Floating point binary types are not among them, but as alternatives are likely to be beyond the scope of this exercise, resorting to float or double will do.

I took into consideration the level of C knowledge of the OP, learning on his/her own, or in a beginners class, when I suggested using floats. Yes, accurate calculations of money would require more advanced code, or a pre-compiled library. I didn't consider it appropriate to suggest a more advanced solution when offering a response that will help the OP (And others) to understand the problem in the code presented.