C++ what is the exit code 4294967295? aka I need help with a program crash.

[LauScript]

I was testing my program and ran into a issue, I read up on it and it is a return exit code, other than that I don't know what it is. this number, "4294967295", gets returned from string.find(" "), when a string that has no space is used. I need to do error handling because my application crashes if the following code can find no space:

string ucmd::getcmd(string full){
       return full.erase(full.find(" "),full.length()-full.find(" "));
};

If it cannot find a space( aka if i supply it a string like "fun" ), the entire program will crash and give a message in the DOS window that says

[quote]
This application has requested the Runtime to terminate it in an unusual way. Please contact the applications support team for more information.
[/quote]

Basically what is the best way to do a check, to make sure the string has a space before I call the getcmd function, or even better check it inside the getcmd function.

thanks

also:

[url]http://bytes.com/topic/c/answers/217841-return-code-4294967295-uint_max[/url]

[Ltp0wer]

I suggest you take a look at [url=http://www.cplusplus.com/reference/string/string/]cplusplus's string reference[/url] if you have anymore questions.

string str = "Hell o";
    if (str.find(" ") != -1)
    {
        cout << "There is a space" << endl;
    }

or

string str = "Hell o";
    if (str.find(" ") != str.npos)
    {
        cout << "There is a space" << endl;
    }

I'm not sure which is better practice.

[jalb]

[QUOTE=Ltp0wer;32823357]I'm not sure which is better practice.[/QUOTE]
Generally it's better to not toss in "magic numbers." If there's a define, constant, or in this case a member that serves the purpose, you should use it instead of what it represents.

In other words, "str.npos" instead of "-1" is better practice.

[LauScript]

worked perfectly, thanks guys

[editline]17th October 2011[/editline]

while i'm here, how can i delete something that i've defined, i don't have the words to explain it but I can show you.

// All of this shit will stay, obviously
class item{
      bool reach;
      public:
             void setreachable(bool);
             bool getreachable();
};

bool item::getreachable(){
     return reach;
};

void item::setreachable( bool reachable ){
     reach = reachable;
};


// now lets say i did

item book;
book.setreachable(true);

// now lets say i want 'book' completely removed, gone. how do i do that. in lua you just do like
// book = nil; how do i do something like that in c++?

[Skipcast]

If it isn't a pointer it should delete itself when it goes out of scope AFAIK (assuming it was created in the same scope). With pointers you have to type "delete book;" to prevent a memory leak.

Atleast i think so, someone correct me if i'm wrong as i haven't written anything in C++ for months :v:

[q3k]

[QUOTE=LauScript;32823712]worked perfectly, thanks guys

[editline]17th October 2011[/editline]

while i'm here, how can i delete something that i've defined, i don't have the words to explain it but I can show you.

// All of this shit will stay, obviously
class item{
      bool reach;
      public:
             void setreachable(bool);
             bool getreachable();
};

bool item::getreachable(){
     return reach;
};

void item::setreachable( bool reachable ){
     reach = reachable;
};


// now lets say i did

item book;
book.setreachable(true);

// now lets say i want 'book' completely removed, gone. how do i do that. in lua you just do like
// book = nil; how do i do something like that in c++?

[/QUOTE]

If you're not using 'new' and are declaring the object in a function, here's what happens:
- Processor starts running function, allocates some space on the stack for it
- Processor executes other code from the function
- Processor gets to 'item book', calls constructor
- Processor executes other code from the function
- Processor hits 'return'. Right before it, the compiler automagically added a destructor call to your item object
- Processor exists from function, the space that was allocated for the object is now marked as free

[LauScript]

Alright, I see.

How can I somehow match a string to a class i've created, again I can't explain it, but I can show you.

#include <cstdlib>
#include <iostream>
#include <string>

using namespace std;

class ucmd{
      public:
            string getarg(string,string);
            string getcmd(string);
};

string ucmd::getcmd(string full){
       if ( full.find(" ") != full.npos ){
          return full.erase(full.find(" "),full.length()-full.find(" "));
       }else{
             return "CMD_FAIL";
       };
};

string ucmd::getarg( string cmd, string full){
       string str = full.substr(cmd.length()+1);
       string err = "Invalid command arguments!";
       
       if ( str.length() < 1 ){
          return err;
       }else if ( str == " " ){
             return err;
       }else if ( str == "" ){
             return err;
       }else{
             return str;
       };
};

class item{
      bool reach;
      string usetext;
      string uid;
      public:
             void setreachable(bool);
             bool getreachable();
             string getusetext();
             void setusetext(string);
             void setuid(string);
};

void item::setuid(string name){
     uid = name;
};

void item::setusetext(string text){
     usetext = text;
};

string item::getusetext(){
       return usetext;
};

bool item::getreachable(){
     return reach;
};

void item::setreachable( bool reachable ){
     reach = reachable;
};

class character{
      item holding;
      
      public:
             void take(item);
             bool canReach(item);
};

bool character::canReach(item name){
     return name.getreachable();
};

void character::take( item name){
     if ( name.getreachable() == true ){
        holding = name;
        //cout << name.getusetext() << endl;
     }else{
           cout << "You can't reach that!" << endl;
     };
};

int main(int argc, char *argv[])
{
    // for storage.
    string cinline;
    
    // so we can use single argument commands :)
    ucmd cmd;
    
    // The player.
    character player;
    
    // Lets do the introduction...
    cout << "You smell the damp, chemical air.. you awake..\n" << endl;
    cout << "As you look around you see a table set afront you, on the table sits a glass beaker, a bunsen burner, a vial labeled as sulphuric acid and a glass dropper \n" << endl;
    cout << "You try to stand up, you find your left hand is handcuffed to the chair, which is bolted to the ground.. what will you do?\n" << endl;
    
    // Alright, now lets create the items we stated in the intro.
    item beaker;
    item acid;
    item glassdropper;
    item burner;
    
    // set their information.
    beaker.setuid( "item_beaker" );
    beaker.setreachable(true);
    beaker.setusetext( "You grab the glass beaker." );
    
    acid.setuid( "item_acid" );
    acid.setreachable(true);
    acid.setusetext( "You grab the vial of acid, don't spill!" );
    
    glassdropper.setuid( "item_glass_dropper" );
    glassdropper.setreachable(true);
    glassdropper.setusetext( "You grab the glass dropper, it has a small rubber pad on the top." );
    
    burner.setuid( "item_burner" );
    burner.setreachable(true);
    burner.setusetext( "You turn the burner on, and it slowly heats up." );
    while( true ){
           
           // Ghetto commands system..
           getline( cin, cinline );
           
           if ( cmd.getcmd(cinline) == "open" ){
              cout << cmd.getarg( "open", cinline ) << endl;
           }else if ( cmd.getcmd(cinline) == "take" ){
                 // i need the cmd.getarg  to somehow link back to the item's UID, and that would go back to the 'item <whatever arg>'
                 player.take( cmd.getarg( "take", cinline) );
          }else{
                cout << "Invalid command!" << endl;
          };
    };
    
    // So it doesn't close incase we pass the while loop.
    system("PAUSE");
};

The important line i'm talking about is

player.take( cmd.getarg( "take", cinline) );

[Ltp0wer]

The way you are currently doing it, you'd need to check what was taken in the character::take function.
If I were you, I'd have the different items as different classes that all inherit from a base item class, and have the player's inventory just be a std::list of items.

Also, Look into what class constructors and destructors are.

If you have anymore simple questions, you should post in the very active help thread. [url]http://www.facepunch.com/threads/1092921[/url]