Question

All commands must be in the command line.

The expense data file is separate.

Programming Project #2: Manage Spending Using Commands Objectives: • Understand how to create and manipulate list of objects using array or vector class • Handle input errors and invalid values • Design and create a well-structure program using C++ basic programming constructs and classes. Description: Each “expense” contains 2 values: the spending amount (double) and its description (string)

Here is an example of the “expense” data file which is simply the list of “expense” entries (one expense per line): 45.25 Monthly telephone and Internet services 200.20 Monthly electric, water and gas 1200 Rent 12.90 Netflix membership 99 Amazon membership 150.50 Weekly movie, music, concert and entertainment 400 Friday restaurant and dining out 50 Monthly gym membership 175.75 Home repair and improvement 333 Yearly Tax and insurance 160 Gift and charitable contributions Implement the command-driven “ManageExpenses” program to support for the following commands:

- show show all spending entries - spend add a new spending entry by asking the amount and the description - amount>= amount-value display only spending entries that have the amount greater or equal to the given amount value - save [filename] save the current list of expenses into a given data file if no file name is given, it will save over the original file - help display the list of supported commands - exit end the program Requirements: 1. The program must produce the same output as provided. 2. The program must check and accept the command line argument of the data file name 3. The program must accept any data file name (e.g. should not hard code the file name in the program) 4. The program must read the data file only once, build the array of data only (and not the data file again). 5. There should be no global variable used in the program 6. Commands are case-insensitive. “SHOW” and “show” should produce the same command output. 7. Give an error message when command line argument for data file name is not given 8. The program should have error checks for incorrect given amount (negative as well as a string instead of a number) 9. The “amount>=” search commands expect one argument. If they don’t give an argument, please display an “invalid” command. Please do not prompt the user to enter the search string or amount separately

Answer 1

#include <iostream> // header file for basic input output

#include<fstream> // header file for File input output

#include <vector> // header file for vectors (dynamic array)

using namespace std;

// Class for various expenses

class Expense{

public:

double spending_amount;

char description[80];

};

int main(int argc, char const *argv[])

{

if(argc<2){

cout<<"Error! Name of the data file not provided. Program will terminate\n";

return -1;

}

string filename = argv[1]; // store filename given as command line argument

fstream input_file_stream; // filestream to read file

input_file_stream.open(filename, ios::in| ios::out| ios::binary); // opening file to read using ios::out flag to create file if it doesn't exist

//Checking if file was successfully opened

if(!input_file_stream.is_open()){

cout<<"Error opening file: "<<filename<<"\n";

return -1;

}

Expense exp;

vector<Expense> exp_arr;

while(input_file_stream.read((char*)&exp, sizeof(exp))){

exp_arr.push_back(exp);

}

input_file_stream.close();

string command="";

ofstream output_file_stream; // to save file

while(true){

cin.clear();

getline(cin,command);

if(command=="exit" || command=="EXIT") // exit if the exit command is given

break;

if(command=="show" || command=="SHOW"){

if(exp_arr.size()==0){

cout<<"File empty. Nothing to display. Please add entries to file using command spend\n";

continue;

}

for(int i=0;i<exp_arr.size();i++){

cout<<exp_arr[i].spending_amount<<" "<<exp_arr[i].description<<"\n";

}

}

else if(command=="spend" || command=="SPEND"){

cout<<"Enter the amount: ";

string num;

cin>>num;

int i;

for(i=0;i<num.length();i++)

if(isalpha(num[i])){

break;

}

if(i==num.length()){

exp.spending_amount = stod(num);

}

else{

cout<<"Invalid amount entered!\n";

continue;

}

// cin>>exp.spending_amount;

if(exp.spending_amount<0){

cout<<"Invalid amount entered!\n";

continue;

}

cout<<"Enter the description: ";

cin.ignore();

cin.getline(exp.description,80);

// cin.clear();

exp_arr.push_back(exp);

}

else if(command.substr(0,8)=="amount>=" || command.substr(0,8)=="AMOUNT>="){

string num = command.substr(8,command.length());

if(num.length()==0){

cout<<"Invalid command!\n";

continue;

}

double amount = stod(num);

for(int i=0;i<exp_arr.size();i++){

if(exp_arr[i].spending_amount>=amount){

cout<<exp_arr[i].spending_amount<<" "<<exp_arr[i].description<<"\n";

}

}

}

else if(command.substr(0,4)=="save" || command.substr(0,4)=="SAVE"){

string fname = command.substr(4,command.length());

if(fname==""){

output_file_stream.open(filename, ios::out | ios::binary);

if(!output_file_stream.is_open()){

cout<<"Error writing to file "<<filename<<"\n";

continue;

}

else{

for(int i=0;i<exp_arr.size();i++){

exp = exp_arr[i];

output_file_stream.write((char*)&exp,sizeof(exp));

}

cout<<"Written successfully to file "<<filename<<"\n";

}

}

else{

fname = command.substr(5,command.length());

output_file_stream.open(fname, ios::out | ios::binary);

if(!output_file_stream.is_open()){

cout<<"Error writing to file "<<fname<<"\n";

continue;

}

else{

for(int i=0;i<exp_arr.size();i++){

exp = exp_arr[i];

output_file_stream.write((char*)&exp,sizeof(exp));

}

cout<<"Written successfully to file "<<fname<<"\n";

}

}

}

else if(command=="help" || command=="HELP"){

cout<<"Help:\n";

cout<<"The supported commands are:\n";

cout<<"1. show: Displays all entries of the expense file\n";

cout<<"2. spend: Add spending entries\n";

cout<<"3. amount>=xxx: Displays all entries whose spending is >= xxx where xxx is a double\n";

cout<<"4. save filename: Save the current records into the file. If filename is not specified, saves to default\n";

cout<<"5. help: Displays this help\n";

cout<<"6. exit: Exits the program\n";

cout<<"These commands are case insensitive\n";

}

else{

cout<<"Invalid command!\n";

}

}

output_file_stream.close();

return 0;

}