Ummmmm... yeah...... C++ help... as usual... - Overclock.net

JoBlo69 · 06-14-07

this is the assignment i have...

I'm not getting this at all... Well, i kinda get it, but only in parts. I'm not sure how to structure it all together for it to work correctly... I have some code with a few functions in it thinking thats the best way to do it... But its not going so well...

Quote:

Assignment:

My friend, Cary Parker, owns a small parking garage downtown. It has 10 stalls, numbered from one to ten. She has asked you write a program in C++ to control the single entrance and exit to the garage. Your program design is as follows:

1) When the program starts it prompts the attendant for whether a car is entering (e), exiting (x), or whether the attendant wishes to quit the program (q). The attendant will enter an e (or E) if the car is entering and an x (or X) if the car is exiting.

You may assume that the garage is empty when the program begins. The steps below should be repeated in a loop, until the attendant decides to terminate the program, or ‘quit’ (by entering a q or Q in response to the prompt), presumably at the end of the day.

2) At any time, if the attendant responds with the letter ‘e’, it indicates that a car is entering the garage. If there is an empty stall, your program should display the first empty stall number. Otherwise it will display a message which says: “Sorry, Lot Full”. Only if there is an empty stall, your program will then prompt the attendant to enter vehicle license of the incoming car. The program will next prompt the attendant to enter the time of day of entrance, by prompting for the hour (1 to 12), then prompting for the minute (0 to 59), and then prompting for am (a) or pm (p). Be sure to validate the input is a valid time, and re-prompt the user in a loop until it is.

3) If the attendant responds with the letter ‘x’, it indicates that a car is exiting the parking garage. In this case, your program should prompt for the vehicle license of the exiting car. If your program shows that a car with that license is currently in the lot it will prompt for the time of exit, in a similar manner to the time of entrance. If that license is not in the lot, your program should display an error. You should check that the time of exit is later than the time of entrance, and display an error message if it is not. Otherwise your program should display a parking receipt for the driver of the exiting car, which should include the following information:

Vehicle License
Stall Number
Time of Entry
Time of Exit
Charge for parking

4) The charge for parking in the lot is as follows:

$2.75 per hour, or part thereof, for the first four hours, and $1.75 per hour, or part thereof, thereafter.
There is a minimum charge for using the lot of $5.50, and a maximum daily charge of $18.00.
There is also a special evening rate of $5.00 for anyone who enters the garage at any time at or after 6pm. If you enter at or after 6pm the price is always $5.00 regardless of the length of time you park.
Note: These prices have changed since the last project you did for Cary Parker.

5) If the attendant responds with a “q”, your program should terminate and display the following summary information:

Total number of cars that have exited the lot (i.e. cars that have entered the lot, parked and exited).
Total number of cars remaining in the lot (i.e. cars that have entered and parked, but not exited).
Total parking charges (for those cars that have exited).
Average length of time parked (in hours and minutes) for those cars that have exited.
Average parking charge (for those cars that have exited).

Design Considerations

Note: It is an essential part of your grade that you design your application according to the considerations below. For example, you must use functions that have the specified signatures, and arrays that have the specified declarations.

1) You need a function which prompts the user for, reads in, and validates a correct time of day. It should display an appropriate error message if any input is invalid (such as an hour greater than 12 or less than 1, a minute greater than 59 or less than zero, and an am/pm designator other than ‘a’ or ‘p’.) It should continue to display error messages, in a loop, until the user enters valid data.

The signature of the function will be: int readTime()

It should return the user’s input converted to the number of minutes since midnight (stored as an integer).

2) You need a function which calculates a parking charge. Its signature should be:

double calculateCharge(int timeIn, int timeOut)

If timeIn is later than timeOut it should return -1.0 (as an error condition) otherwise it will return the amount of the charge for the given period of time. This is a double precision floating-point number representing dollars and cents.

3) You will need an array, declared as int carTimeIn[10], to hold the time that a car entered each stall. Note that carTimeIn[0] will hold the data for stall #1, carTimeIn[1] for stall #2, and so on. carTimeIn[9] holds the data for stall #10. Use a value of minus one (-1) to indicate that there is no car in a particular stall.

Note: In order that all of your functions can access this array – in other words, that the array is in scope for all of the required functions, you will find it easiest to declare the array at file scope in your application.

4) You will need another (“parallel”) array, declared as string carLicense[10], to hold the vehicle license for each auto parked in the various spaces in the lot. Use an empty string (“”) in the case that a stall is empty. This array also must be declared at file scope.

5) You will need a function to find the first empty stall. Its signature will look like this:

int findStall()

It should search the carTimeIn array for the first negative entry, which should be minus one (-1) indicating that the stall is empty, and return the index of that entry. You should remember to add one to the index to calculate the actual stall number. If there are no negative entries, it should return -1 to indicate that the lot is full.

6) You will need a function to specify that a car with a specified vehicle license entered a specified stall at a specified time. The signature will be as follows:

void park(int stallNumber, int timeIn, string license)

Note: You should previously have checked that the stall is empty (by using findStall).

7) You will need a function to “look up” a vehicle license to see if that license is already in the lot, and if so, in what stall. The signature will be as follows:

int find (string license)

This function will return the stall number that contains the designated license. If the license is not found, the return value will be -1.

8) You will need a function to return the carTimeIn value for a designated stall. The signature will be as follows:

int getTimeIn (int stallNumber)

9) You will need a function to specify that a car exited the specified stall. Your function should set the appropriate element of the carTimeIn array to minus one (-1), and the appropriate element of the carLicense array to “”, to indicate that the specified stall is now vacant. The signature will be as follows:

void unpark(int stallNumber)

Note: You should previously have checked that the currently exiting car was actually parked in the designated stall, by using the find method above, and that the time of exit is later than the time of entry.

this is about how far i got...

Code:

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <cmath>
#include <cctype>
#include <cstdlib>

using namespace std;

int readTime();
double calculateCharge(int timeIn, int timeOut);


int main()
{
    int minSinceMidnight = 0;
    double totalCharge = 0;
    int timeArrive = 0;
    int timeExit = 0;

    cout << "Enter the time the car entered the parking lot." << endl;
    timeArrive = readTime();
    cout << "Enter the time the car exited the parking lot." << endl;
    timeExit = readTime();
    if (timeArrive >= 1800)
        totalCharge = 5;
    else
        totalCharge = calculateCharge(timeArrive, timeExit);

    if (totalCharge == -1)
        cout << "Invalid times!" << endl;
    else
        cout << "Total charge = " << setprecision(2) << totalCharge << endl;

    return(0);

}


int readTime()
{
    int totalMin = 0;       //total minutes since midnight
    int iHour = 0;          //value user enters for hour of the day
    bool hourOK = false;    //boolen to use for looping until the user gets input correct
    int iMin = 0;           //value user enters for minute of the hour
    bool minOK = false;     //boolen to use for looping until the user gets input correct
    char cAM;               //char used to store either A or P for am/pm
    bool amOK = false;      //boolen to use for looping until the user gets input correct

    totalMin = 0;   //initialize the total minutes since midnight

    //the user will input the hour of the day and we will loop until they get it correct
    while (!hourOK)
    {
        cout << "Enter hour of day: ";
        cin >> iHour;
        if ((iHour < 0) || (iHour > 12))
            cout << "Hour must be between 0 and 12...please try again." << endl;
        else
            hourOK = true;
    }

    //the user will input the minutes of the hour and we will loop until they get it correct
    while (!minOK)
    {
        cout << "Enter minute of hour: ";
        cin >> iMin;
        if ((iMin < 0) || (iMin > 59))
            cout << "Minute must be between 0 and 59...please try again." << endl;
        else
            minOK = true;
    }

    //the user will input eith A or P (for am/pm) and we will loop until they get it correct
    while (!amOK)
    {
        cout << "Enter A or P (for AM or PM): ";
        cin >> cAM;
        if ((toupper(cAM) != 'P') && (toupper(cAM) != 'A'))
            cout << "You must enter an A or a P...please try again." << endl;
        else
            amOK = true;
    }

    if (toupper(cAM) == 'P')
        totalMin = ((iHour + 12) * 60) + (iMin);
    else
        totalMin = (iHour * 60) + (iMin);
    cout << "Total minutes since midnight = " << totalMin << endl;

    return totalMin;
}

double calculateCharge(int timeIn, int timeOut)
{
    int invalidInput = -1;
    int totalMinutes = 0;
    int totalHours = 0;
    int hourDiff = 0;
    double totalCharge = 0;

    if (timeOut <= timeIn)
        return invalidInput;

    totalMinutes = timeOut - timeIn;
    totalHours = totalMinutes / 60;
    if (totalHours <= 4)
    {
        totalCharge = totalHours * 2.75;
    }
    else
    {
        hourDiff = totalHours - 4;
        totalCharge = (4 * 2.75) + (hourDiff * 1.75);
    }

    if (totalCharge < 5.50)
        totalCharge = 5.50;
    if (totalCharge > 18.00)
        totalCharge = 18.00;

    return totalCharge;
}

I just need some help to tie all together... make it work right...

kdbolt70 · 06-15-07

Reading through this (on my vacation AWAY from my programming job) and I'll check it out. Also bumping in case anyone else wants to chop through this with me. I'll see what I can do.

Below follow edits with comments/opinions

-------------------------------------------------

Edit1:

Quote:

you will find it easiest to declare the array at file scope in your application.

Holy horrible programming practice batman. Global array? duuurrr

Edit2: parallel arrays?? you need to get to object oriented programming ASAP.

Edit3: you need to prototype all your required functions before you even start programming. Get everything they give you down on your file before your brain even starts cranking on how to actually code it.

Edit4: I'm not sure what in the heck you're doing in main()! You need to do error checking for inputs, and you don't ask for the time incoming and the time exiting untill the person inputs "e" or "x". I'm rewriting main.

Edit5: ENUMERATORS.

kdbolt70 · 06-15-07

Ok, holy tired. I'm sitting here at my cottage doing the same thing I took vacation from

guess I can't deny that I'm a total nerd.

This is what I've got. It seems to work, but I'll leave the testing up to you. I don't know which IDE you're using, so I put in the

Code:

system("pause");

line to freeze the console. You can remove these if you don't need them. Also, when I encountered an error (i.e. an exit time entered before an incoming time) I exited the program. you may not want to do that. Again, I didn't stress test or fencepost test this at all. I can almost guarentee its not 100%, but its a ton better then what you had. I also didn't look over the two functions you had already written, as they seemed to work ok in the testing I did. You should definetly look over those (I would've but I figured you'd rather just get an idea of how to set the code up in its entirety). My coding is sloppy, don't take not on the style. I don't like doing assignments for people, but someone did this for me once when I was new to coding and it helped me learn a lot. Let me know if you have any questions.

Code:

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <cmath>
#include <cctype>
#include <cstdlib>

using namespace std;

int readTime(void);
double calculateCharge(int, int);
int findStall(void);
void park(int, int, string);
int find(string);
int getTimeIn(int);
void unpark(int);
int attChoice(void);
int entry(void);


//Globals
int carTimeIn[10];
string carLicense[10];

int main()
{
    double avgCharge =0, totalCharge =0, charge =0; 
    int totalCars=0, totalTime = 0; 
    int carsLeft = 0;
    int avgTime = 0;
    int timeArrive = 0;
    int timeExit = 0;
    
    int openStall, exitedStall;
    string license;
    
    //initialize arrays
    for(int i=0; i<10; i++){
       carTimeIn[i]=-1;
       carLicense[i] = "";
    }
    
    while(true){
       int attChoice = entry();
       
       if(attChoice == -1){
         // quitting
         if(totalCars == 0){
            avgCharge = 0;
         }
         else{avgCharge = totalCharge/(double(totalCars));}
         carsLeft = findStall();  //this will return the number of full stalls
         if(carsLeft == -1){
            carsLeft = 10;
         }
         if(totalCars == 0){
            avgTime = 0;
         }
         else{avgTime = (totalTime/totalCars);}
         cout << "total cars exited: "<< totalCars <<endl;
         cout << "total cars remaining: "<<  carsLeft <<endl;
         cout << "total parking charges: "<< totalCharge<<endl;
         cout << "average duration: "<< avgTime <<endl;
         cout << "average charge: "<< avgCharge << setprecision(2) << endl;
         system("pause");
         return (0);
          
       }
       else if(attChoice == 1){
          openStall = findStall();
          if(openStall == -1){
             cout << "sorry, lot full";
          }
          cout << "Enter the license number of the car entering the parking lot" << endl;
          cin >> license;
          cout << endl;
          cout << "Enter the time the car entered the parking lot." << endl;
          timeArrive = readTime();
          park(openStall, timeArrive, license);
       }
       else if(attChoice == 0){
          cout << "Enter the license number of the car exiting the parking lot" << endl;
          cin >> license;
          cout << endl;
          exitedStall = find(license);
          if(exitedStall == -1){
             cout << "This vehicle never entered the parking lot" << endl;
             system("pause");
             return(0);
          }
          cout << "Enter the time the car exited the parking lot." << endl;
          timeExit = readTime();
          timeArrive = getTimeIn(exitedStall);
          if(timeArrive > timeExit){
             cout << "incorrect exit time";
             system("pause");
             return 0;
          }
          if (timeArrive >= 1800){
             charge = 5;
          }
          else{
             charge = calculateCharge(timeArrive, timeExit);
          }
          
          cout << "Vehicle license: " << license << endl;
          cout << "Stall Number: " << exitedStall << endl;
          cout << "Time of Entry: " << timeArrive << endl;
          cout << "Time of Exit: " << timeExit <<endl;
          cout << "Charge: " << charge << setprecision(2) <<endl;
          
          totalCars++;  //update totals
          totalCharge += charge;
          totalTime += (timeExit-timeArrive);
       }
    }
    
    return(0);

}

int entry(void){
    char choice;
    bool valid = true;
    do{
      cout << "Please select an action: \"E\" for enter, \"X\" for exit, \"Q\" to quit" << endl;
      cin >> choice;
      cout << endl;
      if(choice=='e' || choice=='E'){
       return 1;
      }
      else if(choice=='x' || choice=='X'){
       return 0;
      }
      else if(choice=='q' || choice=='Q'){
       return -1;
      }
      else{
         cout << "invalid selection, please enter again." << endl;
      }
    }while(valid);
    

}


int readTime()
{
    int totalMin = 0;       //total minutes since midnight
    int iHour = 0;          //value user enters for hour of the day
    bool hourOK = false;    //boolen to use for looping until the user gets input correct
    int iMin = 0;           //value user enters for minute of the hour
    bool minOK = false;     //boolen to use for looping until the user gets input correct
    char cAM;               //char used to store either A or P for am/pm
    bool amOK = false;      //boolen to use for looping until the user gets input correct

    totalMin = 0;   //initialize the total minutes since midnight

    //the user will input the hour of the day and we will loop until they get it correct
    while (!hourOK)
    {
        cout << "Enter hour of day: ";
        cin >> iHour;
        if ((iHour < 0) || (iHour > 12))
            cout << "Hour must be between 0 and 12...please try again." << endl;
        else
            hourOK = true;
    }

    //the user will input the minutes of the hour and we will loop until they get it correct
    while (!minOK)
    {
        cout << "Enter minute of hour: ";
        cin >> iMin;
        if ((iMin < 0) || (iMin > 59))
            cout << "Minute must be between 0 and 59...please try again." << endl;
        else
            minOK = true;
    }

    //the user will input eith A or P (for am/pm) and we will loop until they get it correct
    while (!amOK)
    {
        cout << "Enter A or P (for AM or PM): ";
        cin >> cAM;
        if ((toupper(cAM) != 'P') && (toupper(cAM) != 'A'))
            cout << "You must enter an A or a P...please try again." << endl;
        else
            amOK = true;
    }

    if (toupper(cAM) == 'P')
        totalMin = ((iHour + 12) * 60) + (iMin);
    else
        totalMin = (iHour * 60) + (iMin);
    cout << "Total minutes since midnight = " << totalMin << endl;

    return totalMin;
}

double calculateCharge(int timeIn, int timeOut)
{
    int invalidInput = -1;
    int totalMinutes = 0;
    int totalHours = 0;
    int hourDiff = 0;
    double totalCharge = 0;

    if (timeOut <= timeIn)
        return invalidInput;

    totalMinutes = timeOut - timeIn;
    totalHours = totalMinutes / 60;
    if (totalHours <= 4)
    {
        totalCharge = totalHours * 2.75;
    }
    else
    {
        hourDiff = totalHours - 4;
        totalCharge = (4 * 2.75) + (hourDiff * 1.75);
    }

    if (totalCharge < 5.50)
        totalCharge = 5.50;
    if (totalCharge > 18.00)
        totalCharge = 18.00;

    return totalCharge;
}

int findStall(void){
    for(int i = 0; i<10; i++){
            //search through array, find open spot
       if(carTimeIn[i] == -1){
          return i;
       }
    }
    return -1;   //no open spots
}

void park(int stallNumber, int timeIn, string license){
     carTimeIn[stallNumber] = timeIn;
     carLicense[stallNumber] = license;
}


int find(string license){
    for(int i = 0; i<10; i++){
       if(carLicense[i] == license){
          return i;
       }
    }
    return -1;
}

int getTimeIn(int stall){
    return carTimeIn[stall];
}

void unpark(int stall){
     carTimeIn[stall] = -1;
     carLicense[stall] = "";
}

TrAncE XD · 06-15-07

you better rep him LOL

JoBlo69 · 06-15-07

O will... every day for like a year... lol... not really... but i would if i could...

kdbolt70 · 06-15-07

Quote:

Originally Posted by TrAncE XD

you better rep him LOL

Ha, I don't do it for rep, I do it because I was in his position once, annoyed as hell at a stupid school project.

And all my opinion edits before, yeah If I was allowed to use/modify those things I suggested it would have gone twice as fast. I mean not being able to use classes/structs/enums/pairs etc... man made that so tedious.

Hope it helped!

JoBlo69 · 06-15-07

I have the code running... I'm using Bloodshed. I have no problem using a diff compiler if you recommend a free one... Unless you really thing Visual Studio is really that great... lol...

I'll test it hard and see if i can break it... But so far so good!

The gratitude i have for you doing this for me is HUGE! You have no idea how impressed i am that a total stranger help me out so much! On your vacation of all times as well!!!

I cannot say thanks enough times... so i hope this smile will do the trick!

(jk)

DanC · 06-16-07

kind of random, but do you guys know where i can find programs to practice? maybe a site that gives instructions like this, but maybe not as long? i dunno, anything would be cool

JoBlo69 · 06-16-07

errr... not really sure where to start... Thats why im taking classes... lol...

I had no idea how to program my way out of a wet paper bag before i started going to school for it...

But if you find a good source for it online a person should do alright...

The class im taking is all about the online abilities... Assignments and links to help and everything else is all through an online interface called "WebCT"

Not sure if this helps you out at all...

DanC · 06-16-07

that helps...now i know ill probably have to buy book or something, lol

i took a class 2 years ago, learned alot, but then stopped programming since then. i really don't want to forget all the stuff i learned, it's really helpful to know when you want to go into a career that has something to do with computers

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Ummmmm... yeah...... C++ help... as usual...

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