Stream problem (int)

[Gekitatsu]

Long story short I am trying to pull 2 types of data from a file.
A string (which I have now got working) and a int. While these are easy on their own what I am trying to do is not so. I am trying to search through a file for a certain word then extract the information that follows that word. For example search for MONSTER_NAME then extract the rest of the line which holds the monster's name. I have gotten the last part to work, but the problem is when I want to get the WEAPON_DAMAGE and put the value into a int it doesn't work and the int's value remains unchanged.

Here is the code

#include <iostream>
#include <string>
#include <fstream>

using namespace std;

int main()
{
    ifstream in("happy.txt");
    string line;
    string key = "MONSTER_NAME";
    string two = "Weapon_Name";
    string weaponDamage = "Weapon_Damage";
    string dataSought;
    string weaponName;
    int attack = 0;


   // Read the label "attack" followed by the value
   //_file >> label >> attack;

    while( getline(in, line) )
    {
        //weaponDamage >> attack;
        
        if( key == line.substr(0, key.length()) )
        {
            dataSought = line.substr( key.length()+1 );
            cout << dataSought;
        }
        if( two == line.substr(0, two.length()) )
        {
            weaponName = line.substr( two.length());
            cout << weaponName;            
        }
        if( weaponDamage == line.substr(0, weaponDamage.length()))
        {
                        in >> attack;
              
         }
        }
    
      cout << attack;
    cout << endl;
    system("pause");
}

and here is the text file

xxx ... ... ...
xxz ... ... ...
MONSTER_NAME King Fish Crab
Weapon_Name Zanbato
Weapon_Damage 100
xzz ... ... ...

int attack remains at 0.
Now what I want is the program to searched for Weapon_Damage then set a int to the value that follows the word Weapon_Damage.
Sorry I'm just really bad using streams. Hopefully someone can help thanks.

[Ancient Dragon]

>> in >> attack;
The line has already been read. So just convert the substr to an int similar to the previous string values attach = atoi(line.substr(weaponDamage.length()+1);

[Gekitatsu]

>> in >> attack;
The line has already been read. So just convert the substr to an int similar to the previous string values attach = atoi(line.substr(weaponDamage.length()+1);

I changed the code to

if( weaponDamage == line.substr(0, weaponDamage.length()))
        {
               attack = atoi(line.substr( weaponDamage.length()+ 1 ));
              
         }

but I get the same error

cannot convert `std::basic_string<char, std::char_traits<char>, std::allocator<char> >' to `const char*' for argument `1' to `int atoi(const char*)'

[MosaicFuneral]

Or use istringstream instead of atoi().
Just hope that there is a position after line Weapon_Damage.

[Gekitatsu]

Or use istringstream instead of atoi().
Just hope that there is a position after line Weapon_Damage.

a position? The line within the text file is

Weapon_Damage 100

I simply just want to be able to get that 100 into a int.

oh I googled istringstream not sure how to use it? This is the only part of programming I hate. I just don't get streams at all.

[Yiuca]

I changed the code to

if( weaponDamage == line.substr(0, weaponDamage.length()))
        {
               attack = atoi(line.substr( weaponDamage.length()+ 1 ));
              
         }

but I get the same error

cannot convert `std::basic_string<char, std::char_traits<char>, std::allocator<char> >' to `const char*' for argument `1' to `int atoi(const char*)'

attack = atoi(line.substr(weaponDamage.length()+1).c_str()); fixes that problem, I were gonna mention it earlier just as AD posted.

As a side note it is also usually good to check if a file is open before attempting operations with the file usually something like

if (in.is_open())
{
while(getline(in, line)).... rest of code
}
else
cout << "Error Opening File\n";

[Gekitatsu]

attack = atoi(line.substr(weaponDamage.length()+1).c_str()); fixes that problem, I were gonna mention it earlier just as AD posted.

As a side note it is also usually good to check if a file is open before attempting operations with the file usually something like

if (in.is_open())
{
while(getline(in, line)).... rest of code
}
else
cout << "Error Opening File\n";

ah finally thank you. I've been wanting to finish implementing my games weapons/armor/creature, but I want them in files so they can be adjusted without recompiling. Thank you for the help everybody it works now.

[MosaicFuneral]

As a side note it is also usually good to check if a file is open before attempting operations with the file usually something like

if (in.is_open())
{
while(getline(in, line)).... rest of code
}
else
cout << "Error Opening File\n";

That reminds, I don't see it closed after it's done.

[Yiuca]

That reminds, I don't see it closed after it's done.

:D You're right, I totally missed that... Alas I have good excuse at the mo considering I'm not very well at the moment so my head is abit fuzzy!

Well may aswell add to the thread a little & mention that system("PAUSE"); is bad practice also, better to use cin.get() or similar at the end of the program if you don't want it to just close.