Thread: How can I improve my C program?

Hi all. I am fairly new to programming. I started with C since I was a EE student. I have a simple C program that needs to be improved by I don't know what else I could do.

Here's the code (I'm using VS C++ to compile)

Code:

#include "stdafx.h"

int salary = 0;
int fuel = 0;
double toll = 0;
int food = 0;
double balance = 0.00;

int calBalance(void);

int main()
{
    int workDays = 0;

    puts("My console in C to calculate my budget. Every component except salary takes DAILY use.\n");

    printf("Working Days: ");
    scanf("%d", &workDays);

    printf("Salary: ");
    scanf("%d", &salary);

    printf("Fuel: ");
    scanf("%d", &fuel);

    fuel = fuel * workDays;

    printf("Toll: ");
    scanf("%lf", &toll);

    toll = toll * workDays;

    printf("Food: ");
    scanf("%d", &food);

    food = food * workDays;

    calBalance();
    printf("\nBalance: %.2f", balance);
         
    puts("");    

    return 0;
}

int calBalance()
{
    balance = salary - (fuel + toll + food);
  
    return balance;
}

I think I don't need to explain the code since it is very straightforward. I feel like it can't be improved in the context of C(not C++).

Any suggestion?

Thanks.

Originally Posted by Salem

2. Move all your global variables into main.

If I put them into main, then my function

Code:

calBalance()

would not recognize the variable.

Originally Posted by Salem

3. Make your function take parameters.

You mean take every each of the variables? Wouldn't it be too much if I have around 10 variables?

P/S: Sorry for the double post. When I first posted the question, it did not tell me that it needed approval. The page directed me to the forum and I didn't see my thread. I thought I did not click "Submit new thread" properly or something so I posted it again.

Originally Posted by vart

In addition to the above pay attention to the type conversions. For example your balance variable is double, but calBalance function is returning int.

Thanks @vart, I just realized that.

Okay so this is what I got now,

Code:

#include "stdio.h"

double calBalance(int wsalary, int wfuel, double wtoll, int wfood);

int main()
{
    int salary = 0;
    int fuel = 0;
    double toll = 0;
    int food = 0;
    double balance = 0.00;
    int workDays = 0;

    puts("My console in C to calculate my budget. Every component except salary takes DAILY use.\n");

    printf("Working Days: ");
    scanf("%d", &workDays);

    printf("Salary: ");
    scanf("%d", &salary);

    printf("Fuel: ");
    scanf("%d", &fuel);

    fuel = fuel * workDays;

    printf("Toll: ");
    scanf("%lf", &toll);

    toll = toll * workDays;

    printf("Food: ");
    scanf("%d", &food);

    food = food * workDays;

    balance = calBalance(salary, fuel, toll, food);
    printf("\nBalance: %.2f", balance);
    
        
    puts("");    


    return 0;
}

double calBalance(int wsalary, int wfuel, double wtoll, int wfood)
{
    double wBalance = 0.00;
    wBalance = wsalary - (wfuel + wtoll + wfood);
    
    return wBalance;
}

Is it even appropriate practice to put as much parameters in a function? Well, for now I have 4, but I might have around 5~6 more.