In C, it is possible for the functions to call themselves. A function is called recursive. if a statement within the body of a function calls the same function. Sometimes called circular definitio, recursion is thus the process of defining something in terms of itself. Let us now see a simple example of recursion. Suppose we want to calculate the factorial value of an integer. As we know, the factorial of a number is the product of all the integers between 1 and that number. For example, 4 factorial is 4 * 3 * 2 * 1. This can also be expressed as 4! = 4 * stands for factorial. Thus factorial of a number can be expressed in the form of itself.
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