something with QT install

i get the *.run file from the internet, and install it with command:

chmod 777 qt-linux-opensource-5.0.2-x86-offline.run

sh qt-linux-opensource-5.0.2-x86-offline.run

but the QT creator remmand me that i need to configure a compiler for it. i was so surprised because that i know the system have a gcc compiler. so i search the internet to find something useful. and i finally solve this problem with command :

sudo apt-get install g++  

sudo apt-get install libgl1-mesa-dev libglu1-mesa-dev

i cannot understand the meaning of those command, just as what it looking , maybe they are install something like gcc compiler.