CS1 Course Site       Compilation of Powerful Ideas ( Cognitive and Computational ) Top 10 list of Powerful Ideas Flow Control   Such as the If-then-else flow control, The while flow control, and the for flow control are extreamly useful methods of controlling data. while and for are control loops which allow tasks to be reapted a desired number of times. The if-then-else is a control structure which tests if a conditoin is true or false and acts upon a statment block accordingly.