Turn your mind back to the structure tables and hierarchy charts that we used to design algorithms. We used the following chart to describe how we calculate the lngest side of a right-angled triangle.
In this diagram, we see two levels to the program, level 0 being the first row of the diagram, level 1 the second. More complex algorithms may require many more levels to them.
A structure chart looks very similar to a hierarchy chart. The main difference is that we include interfaces to indicate the movement of data and control information.
We use the following symbols in Structure Charts.
Study the following simple example to see how the interfaces are used,