Question

I have been given the following assignment:

Write a function (documentation included) that given the entry and the
exit time of a vehicle in a parking lot, and the hourly rate,
calculates the amount due.

Assumptions:

1. no overnight parking
2. there is no charge for part of an hour
3. the time is given in military style (1:20p.m. is 1320)

You also have to write a test-driver for your function: in main()
declare and initialize as many variables as needed, then call the
function and display the amount.

This is the code:

int calcRate (int entry , int exit);

int main (void)
{
    // Local Declarations
    int entry;
    int exit;

    //Statements
    printf("Please Enter Entry and Exit time(In military style. For example : 9.30am as
           0930)\n");
    scanf("%d %d\n",&entry , &exit);

    double fee = calcRate(entry,exit);

    printf("Your Parking Fees are %f\n", fee);

    return 0;
}   //main

/*==============calcRate================
 This function calculates the cost of parking
 */

double calcRate (int entry,int exit,double cost)
{
    int hours;
    double rate = 2.00;
    //Statements
    hours = (exit-entry)/100;
    cost = hours * rate;

    return (cost);
}
//calcRate

I cannot build it and I am facing problems with it. For example, I get the following error:

Undefined symbols for architecture x86_64: “calcRate(int, int)”, referenced from: _main in Parking.o (maybe you meant: calcRate(int, int, double)

I’m stuck for almost 2 hours now.
Any kind souls out there?

Answer 1

Difference between function declaration and definition

Function Declarations

int calcRate (int entry , int exit);

Definition header

double calcRate (int entry,int exit,double cost)

So either change Declaration or definition header

for Eg:
Change definition header to

int calcRate(int entry,int exit)

and add declare

double cost

within function calcRate.

Instead of

  printf("Please Enter Entry and Exit time(In military style. For example : 9.30am as 0930)\n");
  scanf("%d %d\n",&entry , &exit);

Do

 printf("Please Enter Entry (In military style. For example : 9.30am as 0930)\n");
 scanf("%d",&entry);
 printf("\n Please exit Entry (In military style. For example : 9.30am as 0930)\n");  
 scanf("%d",&exit);        

No “\n” within scan.

EDIT:

In case of overnightparking

Instead of

hours = (exit-entry)/100;

use

if(exit>entry)
    hours = (exit-entry)/100;
else
    {
        int overnightHours;
        overnightHours = (entry-exit)/100;
        hours=2400-overnightHours;
    }

This will remove negative value.