Simple first program - Logical Issues?

rcast (42)
This is my first program attempt in C++. I'm having some logical issues in a program I wanted to made to test my knowledge on C++ so far after reading up through chapter 3 of "Thinking in C++" - by Bruce Eckel.

It's suppose to be a word processor - I broke up different tasks into functions so that I could have the menu continue to display menu options after each function and only quit the program when I press c.

However, the program's menu function is acting odd - repeating twice some times before it performs the wanted function and when I try to select a new document for the second time, after I already have created a new document and saved it, it just exits.

Can somebody help me see my logical mistakes?


Code:
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// Menu.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <string>
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
	return 0;
}

int menu() {
  bool quit = false;  // Flag for quitting
  		cout << "Select an option below:" << endl;
		cout << endl;
  while(quit == false) {
	  cout << endl;
		cout << "a.) Create new text document" << endl;
		cout << "b.) View an existing text document" << endl;
		cout << "c.) Exit" << endl;
		cout << endl;
		cout << endl;
		char option;
		cin >> option;
		cout << endl;
    switch(option) {
      case 'a' : return 1;
		         quit = true;
                 break;
      case 'b' : return 2;
		         quit = true;
                 break;
      case 'c' : return 3;
                 quit = true;
                 break;
      default  : cout << "Please use a,b,or c!"
                 << endl;
    }
  }
} ///:~



void newFile() {
	// Create user .txt file and populate with user input
	string userFilename;
	cout << "Please name your new text document." << endl;
	cin >> userFilename;
	cout << endl;
	cout << endl;

	// Create file and accept user input
	ofstream myfile;
	userFilename += ".txt";
	myfile.open (userFilename.c_str());
	string input;
	cout << "Please enter the content to be saved into file." << endl;
	cout << "To save & close file, enter (s)ave." << endl;
	cout << "This program can accept multiple lines." << endl;
	cout << " " << endl;
	while (input != "s") {
		getline (cin, input);
		myfile << input << "\n";
	}
	myfile.close();
	cout << " " << endl;
	
	cout << "Your file has been saved." << endl;
	cout << "What would you like to do now?" << endl;
	cout << " " << endl;
	cout << " " << endl;
}



void viewFile() {
	vector<string> v;
	string userFilename;
	cout << "Enter the filename of the file you want to view: ";
	cin >> userFilename;
	userFilename += ".txt";
	cout << endl;
	cout << endl;
	ifstream in(userFilename.c_str());
	string line;
	cout << "Displaying file: "+ userFilename +"." << endl;
	cout << endl;
	while(getline(in, line)) {
		v.push_back(line);
	}
	for(int i = 0; i < v.size(); i++)
		cout << v[i] << endl;
}





int main() {
	cout << "Rocco Text Processor v1.0" << endl;
	cout << " " << endl;
	cout << " " << endl;
	if (menu() == 1)
		newFile();
	if (menu() == 2)
		viewFile();
	if (menu() == 3)
		cout << "Exiting" << endl;
	
	menu(); // Run menu
}
BHXSpecter (982)
Well without running it, the first thing that jumps out at me is your main function. You are checking menu() returns before you even show the menu.

Should be: 

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menu(); // run menu
if(menu() == 1)
    newFile();
// rest of if statements


Also might want to consider making it so the choice is put in a variable and use that to check against rather then the functions return value directly. 
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 int choice = menu();
// then do something like 
if(choice == 1)
   newFile();
// etc
Last edited on
L B (3816)
@BHXSpector how could you miss that each time an if statement is evaluated it calls menu() again? ;)

@OP you need to call menu() ONCE at the start of the program and store its return value in a variable, then sue that variable in the if statements. Otherwise each if statement calls the menu() again.
Last edited on
rcast (42)
How do I get the return value of menu() into a variable?
Last edited on
rcast (42)
ok nevermind about that last quesiton - 

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	int selection = menu(); // run menu
	if (selection==1)
		newFile();
	if (selection==2)
		viewFile();
	if (selection==3)
		cout << "Exiting" << endl;


however, I still don't have the functionality I need. It's completing the function I want but exiting directly after and not re-displaying the menu

Maybe i should throw that entire statement above into a while loop, testing for the exit menu item?
Last edited on
iseeplusplus (363) 

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    switch(option) {
      case 'a' : return 1;   //this exits your function
		         quit = true;  //this can never execute 
                 break;
      case 'b' : return 2;   //same
		         quit = true; //same
                 break;
      case 'c' : return 3;    //...
                 quit = true;    //..
                 break;
      default  : cout << "Please use a,b,or c!"
                 << endl;
    }



Why don't you just do what your doing in main strait from the menu?

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    switch(option) {
      case 'a' : newFile();
                 break;
      case 'b' : viewFile();
                 break;
      case 'c' : cout << "Exiting" << endl;
                 quit = true; 
                 break;
      default  : cout << "Please use a,b,or c!"<< endl;
    }



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int main() {
	cout << "Rocco Text Processor v1.0" << endl;
	menu(); // Run menu
}
Last edited on
rcast (42)
@iseeplusplus - This works! I failed to circle back to this reasoning for some reason. The program works great! Thanks for all your help.


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// Menu.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <string>
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
	return 0;
}


void newFile() {
	// Create user .txt file and populate with user input
	string userFilename;
	cout << "Please name your new text document." << endl;
	cin >> userFilename;
	cout << endl;
	cout << endl;

	// Create file and accept user input
	ofstream myfile;
	userFilename += ".txt";
	myfile.open (userFilename.c_str());
	string input;
	cout << "Please enter the content to be saved into file." << endl;
	cout << "To save & close file, enter (s)ave." << endl;
	cout << "This program can accept multiple lines." << endl;
	cout << " " << endl;
	while (input != "s") {
		getline (cin, input);
		myfile << input << "\n";
	}
	myfile.close();
	cout << " " << endl;
	
	cout << "Your file has been saved." << endl;
	cout << "What would you like to do now?" << endl;
	cout << " " << endl;
	cout << " " << endl;
}



void viewFile() {
	vector<string> v;
	string userFilename;
	cout << "Enter the filename of the file you want to view: ";
	cin >> userFilename;
	userFilename += ".txt";
	cout << endl;
	cout << endl;
	ifstream in(userFilename.c_str());
	string line;
	cout << "Displaying file: "+ userFilename +"." << endl;
	cout << endl;
	while(getline(in, line)) {
		v.push_back(line);
	}
	for(int i = 0; i < v.size(); i++)
		cout << v[i] << endl;
}




void menu() {
  bool quit = false;  // Flag for quitting
  		cout << "Select an option below:" << endl;
		cout << endl;
  while(quit == false) {
	  cout << endl;
		cout << "a.) Create new text document" << endl;
		cout << "b.) View an existing text document" << endl;
		cout << "c.) Exit" << endl;
		cout << endl;
		cout << endl;
		char option;
		cin >> option;
		cout << endl;
    switch(option) {
      case 'a' : newFile();
                 break;
      case 'b' : viewFile();
                 break;
      case 'c' : cout << "Exiting" << endl;
                 quit = true;
                 break;
      default  : cout << "Please use a,b,or c!"
                 << endl;
    }
  }
} ///:~



int main() {
	cout << "Rocco Text Processor v1.0" << endl;
	cout << " " << endl;
	cout << " " << endl;
	menu();
}
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