Following a flowchart

Following a flowchart means starting at the Start terminator, carrying out each step in the order the arrows show, choosing the correct path at each decision, and continuing until you reach the End terminator. To find the outcome for a given input, trace that input through the process steps and decision questions until you reach the final output.

Tracing an input

Imagine a flowchart for a bike hire desk. It starts by taking the rider's age and the hire length as input. The first decision asks Is the rider under 12? If Yes, it outputs “Junior helmet needed” and ends. If No, it asks: Is the hire longer than 2 hours? If Yes, it outputs “Free water bottle”; if No, it outputs “Standard hire”. Every path then reaches End.

For a 14-year-old hiring for 3 hours, start at Start, input 14 and 3, answer No to the first decision, answer Yes to the second decision, and reach the output “Free water bottle” before End. The outcome is that message. For a 10-year-old, the first decision answer is Yes, so you follow that path to “Junior helmet needed” and do not visit the second decision at all: only the chosen exit from a decision is followed.

Work through the steps in sequence and keep the input value in mind, because later decisions and outputs depend on it. The final output you reach is the flowchart's outcome for that input.