Standard methods, trace tables, validation and test data

Learning objectives

Write algorithms that total, count, find an average and find the largest and smallest values in a set of data, using a suitable loop and a rogue value or a counter to end the input

Write and explain a linear search of a list, and a bubble sort that repeatedly compares and swaps neighbouring values until a pass makes no swaps

Complete a trace table for a given algorithm and set of test data, recording the value of every variable and every output at each pass of the loop

Use a completed trace table to locate a logic error in an algorithm and state the corrected line

Distinguish validation from verification, and describe range, length, type, presence, format and check digit checks, and double entry and visual checks

Choose normal, abnormal, extreme and boundary test data for a stated condition, and explain what each item of test data is meant to reveal