I'm using Eclipse c++ and when I run a program it says: launch failed. Binary not found.

how can i fix this?

Executing c/c++ program with eclipse+unix base plate-forme, it requied object file of the program to execute/run it. So first of all you need to build your program by just pressing Ctr+b to buid it. This will create an object file that was required. Now you enabled to run/execute your programe. Good luck :)