In HEP, the principle computational language was, for several decades, Fortran. In the early 1990s OO (Object Oriented) languages such a C++ and Java began to make an impact and today C++ dominates in off-line applications such as Monte Carlo, Event Reconstruction and Physics Analysis. However Fortran still plays a significant part in a number of experiments, particularly those that are well into the data taking stage.
We won't attempt to teach these languages here but the following are useful resources:-