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Home Fruitful functions Composition of Expressions  
See also: Composition  
Composition of Expressions
As you should expect by now, once you define a new function, you can use it as part of an expression, and you can build new functions using existing functions. For example, what if someone gave you two points, the center of the circle and a point on the perimeter, and asked for the area of the circle?
The second step is to find the area of a circle with that radius, and return it. double result = area (radius);return result; Wrapping that all up in a function, we get: double fred (double xc, double yc, double xp, double yp) {double radius = distance (xc, yc, xp, yp); double result = area (radius); return result; } The name of this function is fred, which may seem odd. I will explain why in the next section. The temporary variables radius and area are useful for development and debugging, but once the program is working we can make it more concise by composing the function calls: double fred (double xc, double yc, double xp, double yp) {return area (distance (xc, yc, xp, yp)); }


Home Fruitful functions Composition of Expressions 