Programming Forums > Application Development > C++

brokenhope · Apr 25th, 2005, 10:05 PM

Well the title explains it, im just making this to practice a few things ive learned. Im not sure how I will be able to do the editor or deleter, seems like it will be very hard, but ill deal with it when I come to it. Basicaly this stores everything to a .txt file and the program manipulates it.

First thing im having trouble with is making a while loop that never ends, since this will be the menu it will always be refrered back to when your done with the function...

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#include <iostream.h>
#include <stdlib.h>
#include <fstream.h>

// Variables
char choice1;
char choice2;
// Functions
void mainMenu();
void addNote();
void delNote();
void edtNote();
void viwNote();
using namespace std;

int main()
{
    mainMenu();
    system("PAUSE");
    return 0;
}

void mainMenu()
{
    while (choice1) {
    cout << "Main Menu/n1. Add Note/n2. Delete Note/n3. Edit Note/n4. View Notes\n\nOption: ";
    cin >> choice1;

         switch ( choice1 ) {
              case  '1':
              addNote();
              break;
              case '2':
              delNote();
              break;
              case '3':
              edtNote();
              break;
              case '4':
              viwNote();
         }
    }
}

void addNote() {
}
void delNote() {
}
void edtNote() {
}
void viwNote() {
}

I wanted to use gets() to get the input but it wouldnt work at all, so im stuck with cin. Anyways back to the loop I was trying to use while(choice1) { to work as long as choice1 exists but that doesnt work, it starts off as null, and sometimes it will be valueless, so im not even gonna try to make a piece of crap to get that to work, any ideas?

bl00dninja · Apr 25th, 2005, 10:27 PM

the easiest way to do a loop like you want is to start it with this expression here

(Toggle Plain Text)

while(1)
{
}

that automatically evaluates to true and will loop forever. then whenever you want to exit the loop you add the keyword

(Toggle Plain Text)

break;

after any time you want to exit the loop, usually when the user wants to quit the program.
you also use the keyword

(Toggle Plain Text)

continue;

after any time you want to start back up at the beginning of the loop

try something like this:

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#include <stdio.h>

int main()
{
  while(1)
  {
    char uchoice;

    puts("wanna quit?");
    scanf("%c", &uchoice);

    if (uchoice == 'y')
    {
      break;
    }

  }

return 0;

}

or in C++

(Toggle Plain Text)

#include <iostream>
using namespace std;

int main()
{
  while(1)
  {

    char uchoice;

    cout<<"wanna quit?"<<endl;
    cin>>uchoice;
    
    if (uchoice == 'y')
    {
      break;
    }
  }
return 0;
}

brokenhope · Apr 25th, 2005, 10:40 PM

Ah thanks, I also updated the code a bit so its a little better... but the next thing I want to do is try to prevent overflows... since sometimes there will be more than 1000 characters inputed, so I dont know what to do in this case... what ive got is:

(Toggle Plain Text)

void addNote() {
cout << "Enter the text for the note: ";
char note[1000];
cin.ignore();
gets ( note );
cout << note;
}

Whenever I enter more than 1000 the application is forced to close, so any ways to prevent overflows? or automaticaly assign more memory? I think I read something about this in a dynamic memory tutorial but I didnt understand it much...

Josef_Stalin · Apr 25th, 2005, 11:06 PM

Here's an educated guess. Make a function similar to "gets" which checks to see if it is 1000 or smaller first before it inserts it.

bl00dninja · Apr 26th, 2005, 1:53 AM

this is one of those cases when you want to use malloc(C) or new(C++) to allocate your memory dynamically. this way, when you have LESS than 1000, you're not wasting any space. however, this gets more into pointers and the like so i would suggest doing what stalin said and test for your "fullness" condition BEFORE adding data to the array.

i'm a little drunk right now so "beer" with me...this might do it, but i'm not sure

(Toggle Plain Text)

if (note[999] != NULL)
    {
         cout<<"too much data!"<<endl;
         //<--now do something here to skip it, exit, whatever
    }

Ooble · Apr 26th, 2005, 1:41 PM

Don't use gets - instead, use scanf or fgets, which both include ways to disregard more than x characters:

(Toggle Plain Text)

scanf("%999s", &note);
OR
fgets(note, 999, stdin);

Infinite Recursion · Apr 26th, 2005, 2:05 PM

since this is C++, I'd drop the char* type and use the string type... makes life much easier...

The infinite loop... I like do do this...

#define EVER ;;

for (EVER)
{
...code to exe ...
...break condition here...
}

Ooble · Apr 26th, 2005, 2:12 PM

There's another point. Instead of your while loop, wouldn't this make more sense?

(Toggle Plain Text)

char choice;

do
{
    cout << "Wanna quit?" << endl;
    cin >> choice;
}
while ((uchoice | 0x20) != 'y');

Infinite Recursion · Apr 26th, 2005, 3:16 PM

I still like the forEVER idea.

brokenhope · Apr 26th, 2005, 5:31 PM

Hmm I like the ideas, but while(1) works, and the thing ooble posted, I dont really know do that well, I guess it would make sense, maybe ill improve on it when its completly done, im not that concerned with the execution of the menu at this time...

anyways, about the memory stuff, I didnt really want to limit to 1000 characters, I want you to be able to enter a near unlimited amount... is that possible?

Apr 25th, 2005, 10:05 PM	#1
brokenhope Hobbyist Programmer Join Date: Apr 2005 Posts: 126 Rep Power: 4	Making a Note Adder/ Editor/ Deleter/ Viewer thingy Well the title explains it, im just making this to practice a few things ive learned. Im not sure how I will be able to do the editor or deleter, seems like it will be very hard, but ill deal with it when I come to it. Basicaly this stores everything to a .txt file and the program manipulates it. First thing im having trouble with is making a while loop that never ends, since this will be the menu it will always be refrered back to when your done with the function... (Toggle Plain Text) #include <iostream.h> #include <stdlib.h> #include <fstream.h> // Variables char choice1; char choice2; // Functions void mainMenu(); void addNote(); void delNote(); void edtNote(); void viwNote(); using namespace std; int main() { mainMenu(); system("PAUSE"); return 0; } void mainMenu() { while (choice1) { cout << "Main Menu/n1. Add Note/n2. Delete Note/n3. Edit Note/n4. View Notes\n\nOption: "; cin >> choice1; switch ( choice1 ) { case '1': addNote(); break; case '2': delNote(); break; case '3': edtNote(); break; case '4': viwNote(); } } } void addNote() { } void delNote() { } void edtNote() { } void viwNote() { } #include <iostream.h> #include <stdlib.h> #include <fstream.h> // Variables char choice1; char choice2; // Functions void mainMenu(); void addNote(); void delNote(); void edtNote(); void viwNote(); using namespace std; int main() { mainMenu(); system("PAUSE"); return 0; } void mainMenu() { while (choice1) { cout << "Main Menu/n1. Add Note/n2. Delete Note/n3. Edit Note/n4. View Notes\n\nOption: "; cin >> choice1; switch ( choice1 ) { case '1': addNote(); break; case '2': delNote(); break; case '3': edtNote(); break; case '4': viwNote(); } } } void addNote() { } void delNote() { } void edtNote() { } void viwNote() { } I wanted to use gets() to get the input but it wouldnt work at all, so im stuck with cin. Anyways back to the loop I was trying to use while(choice1) { to work as long as choice1 exists but that doesnt work, it starts off as null, and sometimes it will be valueless, so im not even gonna try to make a piece of crap to get that to work, any ideas?

Apr 25th, 2005, 10:27 PM	#2
bl00dninja Programming Guru Join Date: Oct 2004 Location: namespace std Posts: 1,246 Rep Power: 6	the easiest way to do a loop like you want is to start it with this expression here (Toggle Plain Text) while(1) { } while(1) { } that automatically evaluates to true and will loop forever. then whenever you want to exit the loop you add the keyword (Toggle Plain Text) break; break; after any time you want to exit the loop, usually when the user wants to quit the program. you also use the keyword (Toggle Plain Text) continue; continue; after any time you want to start back up at the beginning of the loop try something like this: (Toggle Plain Text) #include <stdio.h> int main() { while(1) { char uchoice; puts("wanna quit?"); scanf("%c", &uchoice); if (uchoice == 'y') { break; } } return 0; } #include <stdio.h> int main() { while(1) { char uchoice; puts("wanna quit?"); scanf("%c", &uchoice); if (uchoice == 'y') { break; } } return 0; } or in C++ (Toggle Plain Text) #include <iostream> using namespace std; int main() { while(1) { char uchoice; cout<<"wanna quit?"<<endl; cin>>uchoice; if (uchoice == 'y') { break; } } return 0; } #include <iostream> using namespace std; int main() { while(1) { char uchoice; cout<<"wanna quit?"<<endl; cin>>uchoice; if (uchoice == 'y') { break; } } return 0; } __________________ i put on my robe and wizard hat... Have you ever heard of Plato, Aristotle, Socrates?...Morons.

Apr 25th, 2005, 10:40 PM	#3
brokenhope Hobbyist Programmer Join Date: Apr 2005 Posts: 126 Rep Power: 4	Ah thanks, I also updated the code a bit so its a little better... but the next thing I want to do is try to prevent overflows... since sometimes there will be more than 1000 characters inputed, so I dont know what to do in this case... what ive got is: (Toggle Plain Text) void addNote() { cout << "Enter the text for the note: "; char note[1000]; cin.ignore(); gets ( note ); cout << note; } void addNote() { cout << "Enter the text for the note: "; char note[1000]; cin.ignore(); gets ( note ); cout << note; } Whenever I enter more than 1000 the application is forced to close, so any ways to prevent overflows? or automaticaly assign more memory? I think I read something about this in a dynamic memory tutorial but I didnt understand it much...

Apr 26th, 2005, 1:53 AM	#5
bl00dninja Programming Guru Join Date: Oct 2004 Location: namespace std Posts: 1,246 Rep Power: 6	this is one of those cases when you want to use malloc(C) or new(C++) to allocate your memory dynamically. this way, when you have LESS than 1000, you're not wasting any space. however, this gets more into pointers and the like so i would suggest doing what stalin said and test for your "fullness" condition BEFORE adding data to the array. i'm a little drunk right now so "beer" with me...this might do it, but i'm not sure (Toggle Plain Text) if (note[999] != NULL) { cout<<"too much data!"<<endl; //<--now do something here to skip it, exit, whatever } if (note[999] != NULL) { cout<<"too much data!"<<endl; //<--now do something here to skip it, exit, whatever } __________________ i put on my robe and wizard hat... Have you ever heard of Plato, Aristotle, Socrates?...Morons. Last edited by bl00dninja; Apr 26th, 2005 at 1:58 AM.

Apr 26th, 2005, 1:41 PM	#6
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Don't use gets - instead, use scanf or fgets, which both include ways to disregard more than x characters: (Toggle Plain Text) scanf("%999s", &note); OR fgets(note, 999, stdin); scanf("%999s", &note); OR fgets(note, 999, stdin); __________________ Me :: You :: Them

Apr 25th, 2005, 11:06 PM	#4
Josef_Stalin Programmer Join Date: Apr 2005 Posts: 77 Rep Power: 4	Here's an educated guess. Make a function similar to "gets" which checks to see if it is 1000 or smaller first before it inserts it.

Apr 26th, 2005, 2:05 PM	#7
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,473 Rep Power: 8	since this is C++, I'd drop the char* type and use the string type... makes life much easier... The infinite loop... I like do do this... #define EVER ;; for (EVER) { ...code to exe ... ...break condition here... } __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Apr 26th, 2005, 2:12 PM	#8
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	There's another point. Instead of your while loop, wouldn't this make more sense? (Toggle Plain Text) char choice; do { cout << "Wanna quit?" << endl; cin >> choice; } while ((uchoice \| 0x20) != 'y'); char choice; do { cout << "Wanna quit?" << endl; cin >> choice; } while ((uchoice \| 0x20) != 'y'); __________________ Me :: You :: Them

Apr 26th, 2005, 3:16 PM	#9
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,473 Rep Power: 8	I still like the forEVER idea. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Apr 26th, 2005, 5:31 PM	#10
brokenhope Hobbyist Programmer Join Date: Apr 2005 Posts: 126 Rep Power: 4	Hmm I like the ideas, but while(1) works, and the thing ooble posted, I dont really know do that well, I guess it would make sense, maybe ill improve on it when its completly done, im not that concerned with the execution of the menu at this time... anyways, about the memory stuff, I didnt really want to limit to 1000 characters, I want you to be able to enter a near unlimited amount... is that possible?

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Programming Forums > Application Development > C++

Making a Note Adder/ Editor/ Deleter/ Viewer thingy