I am following this PHP Google+ tutorial and I am trying to install composer in my WAMP directory
C:\\wamp\\www\\gplus-quickstart-php>curl -s https://getc
If using phpstorm you can download composer using their built in composer option in the tools menu.
You can run it from CLI by locating your php.exe, e.g
C:\wamp\bin\php\php7\php.exe composer.phar install