I am trying to write a program in TI BASIC (TI 83 plus calculator programming) by converting a C++ program I made, but I can't make an If-Else If statement. Does anyone know how I can write If-Else If in TI BASIC? If not, is there a site that can convert C++ to TI BASIC?

PS I am programming in TI BASIC because I can carry my calculator with me, but not my desktop.