C++ matching variable comparisions

websinger · 08-30-2006, 02:41 PM

Hi Im tring to do a simple match here , and that which should match
isn't . it's a pretty simple program. but I dont see the problem

anyone have an inkling?

thanks

Jeff

Code:

~$ cat argtest.c++
#include<iostream>
using namespace std;

int main(int argc, char * argv[])
{
    char *x;
    x=argv[1];

    cout << " the value of X is "<<x<<endl;

    if( x == "xy" )cout<< "it matches !"<<endl;
    else cout<<" no match:"<< endl;
}

~$ g++ argtest.c++ -oargtest
~$ ./argtest xy
the value of X is xy
no match:

other useful (?) info
:~$ g++ -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-checking=release x86_64-linux-gnu
Thread model: posix
gcc version 4.1.2 20060814 (prerelease) (Debian 4.1.1-11)

xhi · 08-30-2006, 02:49 PM

use strcmp to compare your strings

Code:

if(!strcmp(x, "xy"))  // strcmp returns 0 on match
  cout << "it matches !" << endl;

also

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xhi · 08-30-2006, 02:54 PM

or use std::string

Code:

string argtwo;
if(argc > 1)
    argtwo = argv[1];
if(argtwo == "xy")
  cout << "it matches !" << endl;

also

see how neatly that example is formatted, with spacing and all. that is because i

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