Read Something After a Word

nathanpc · 07-31-2009, 08:10 PM

Hello,
I'm building a simple interpreter of a language that i'm developing, but how i can do a cout of something that is after a word and in rounded by "", like this:

Code:

#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
using namespace std;
int main( int argc, char* argv[] )
{

    if(argc != 2)
    {
       cout << "Error syntax is incorrect!\nSyntax: " << argv[ 0 ] << " <file>\n";
      return 0;
    }
    ifstream file(argv[ 1 ]);
    if (!file.good()) {
       cout << "File " << argv[1] << " does not exist.\n";
      return 0;
    }
    string linha;
    while(!file.eof())
    {
    getline(file, linha);
    if(linha == "print")
      {
         cout << text after print;
      }
    }
  return 0;
}

And how i can remove the "" when printing the text. Here is the file example:

Code:

print "Hello, World"

Thanks,
Nathan Paulino Campos

Yarin · 08-02-2009, 12:16 PM

Read this, it'll make your task a lot easier for you.

Daved · 08-02-2009, 12:52 PM

If you use getline, it reads the entire line. So the entire print "Hello, World" text will be in the linha variable. You'll have to use string functions to remove the "print" and the double quotes.

If all the commands are one word (no spaces) then you could just read in the first word of each line with operator >>. Then if it is "print" you could use getline to read the rest of the line, although you'd still have to get rid of the quotes.

07-31-2009, 08:10 PM	#1
nathanpc Trying to Learn C Join Date: Jul 2009 Location: Brazil Posts: 32	Read Something After a Word Hello, I'm building a simple interpreter of a language that i'm developing, but how i can do a cout of something that is after a word and in rounded by "", like this: Code: #include <iostream> #include <fstream> #include <string> #include <cstdlib> using namespace std; int main( int argc, char* argv[] ) { if(argc != 2) { cout << "Error syntax is incorrect!\nSyntax: " << argv[ 0 ] << " <file>\n"; return 0; } ifstream file(argv[ 1 ]); if (!file.good()) { cout << "File " << argv[1] << " does not exist.\n"; return 0; } string linha; while(!file.eof()) { getline(file, linha); if(linha == "print") { cout << text after print; } } return 0; } And how i can remove the "" when printing the text. Here is the file example: Code: print "Hello, World" Thanks, Nathan Paulino Campos __________________ Eee PC 904HD White \| Windows XP Home Edition \| My Site Google Talk: eeepc904@gmail.com ICQ: 424738586 Add me and let's talk about C and C++!
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08-02-2009, 12:16 PM	#2
Yarin Unregistered User Join Date: Jul 2007 Posts: 925	Read this, it'll make your task a lot easier for you. __________________ GCC 4.4.0, Code::Blocks 8.02, Fedora 11, x64
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08-02-2009, 12:52 PM	#3
Daved Registered User Join Date: Jan 2005 Posts: 7,137	If you use getline, it reads the entire line. So the entire print "Hello, World" text will be in the linha variable. You'll have to use string functions to remove the "print" and the double quotes. If all the commands are one word (no spaces) then you could just read in the first word of each line with operator >>. Then if it is "print" you could use getline to read the rest of the line, although you'd still have to get rid of the quotes.
Daved is offline

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