Find the Bug A Book of Incorrect Programs

F–Forgotten

F.init

Many errors are caused by the programmer wanting the computer to “Do what I mean, not what I say.” The most basic case of this is an instruction that is accidentally left out of the program. One of the most common types of instructions to leave out are ones that initialize variables. This is an F.init error.

Many variables are not initialized when they are defined, and many languages do not assign a default value in this case, which results in the variable containing whatever value happens to be in the memory location the variable is stored at. An uninitialized variable becomes a bug when it is actually used in code that expects it to be initialized. Usually, this error happens because certain paths through the code avoid the ...