3. Functions - CS2030S Programming Methodology II

Another important abstraction provided by a programming language is the function (or procedure). This abstraction allows programmers to group a set of instructions and give it a name. The named set of instructions may take one or more variables as input parameters, and return one or more values. Like all other abstractions, defining functions allow us to think at a higher conceptual level. By composing functions at increasingly higher level of abstractions, we can build programs with increasing level of complexity. Functions help us deal with complexity in a few ways: Functions allow programmers to compartmentalize computation and its effects. We can isolate the complexity to within its body: the intermediate variables exists only as local variables that has no effect outside of the function. A function only interacts with the rest of the code through its parameters and return value, and so, reduces the dependencies between variables to these well-defined interactions. Such compartment

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• Tejas Garrepally