I have composer installed on windows 8.1. I use it to download drupal distributions and modules. I have also installed acquia dev desktop. As you know that dev desktop comes with different versions of php and it has separate folders for it. I have setup composer to use php 5.6. How can I make it use php 7?
Should I uninstall composer and install again or what?
IF you have multiple php version installed in your system
you can run composer with different versions like
In linux
PHP
usr/local/php usr/bin/composer install
for PHP 7.1
usr/local/php7.1 /usr/local/composer install
actually the idea is which version you wants to run get its bin path and then run the composer.
In Windows.
path/to/php.exe composer install
Hope this helps