Firstly, theoretically, any programming language that can be compiled into machine code for the robot's microcontroller could be used. C and C++ are common.
That's no reason to be rude and unhelpful. You may not have noticed, but this is a help forum. If he had posted "HOW TO MAKE ROBOTS WITH C++" then your post would be correct. But as he generally wanted help and is asking a genuine question about the subject (I'm not saying I know anything about it), he deserves to have his question answered as well as possible.
Well i think that you can program a robot with c++ but you may need to learn more about c++ (suggestion) but i do know that if you do want to make a robot's program in c++ you will need to explain like what kind of robot that you want to make like i would start out with taking an old r/c car and try to mount it into your computer with a electronic tool called a breadbox its a white square that has like 500 + holes in it that grab your chips, wires, and powersupply but for the program you will need it to have something like a object sensor like so it knows to stop when someone or something crosses its path also for safety take a 10ft cable and keep it with you all the time and have a kill switch if something goes wrong, also you will need to program alot more into it if you want alot more info on what you will need 'pm' me and i will try to help with what you will need but im not real positive that c++ will work for what you will need but then again maybe you can but its not gonna be easy and now you have got me hooked on this idea im gonna be doing alot of searches on how to program this thing but im currently busy building a mathsolver