Sorry for the delay, but I was actually going to post about Loops. I am trying to make a calculator that accepts inputs and outputs also if one is wrong they can go back, and that is when the loop goes in. I also want to make it receive special equations like area and volume (depending on the shape). Also I wanted to make it accept logarithms and natural logs and if possible even graph with Cartesian coordinates. I'll post my code soon, maybe until I can figure out how to make implicit differentiation on this thing. Maybe in two or three days. Thanx