Calling the function generates a value, which we usually assign to a variable or use as part of an expression. In this chapter, we are finally going to write fruitful functions. The first example is area, which returns the area of a circle with the given radius: Sometimes it is useful to have multiple return statements, one in each branch of a conditional:
Buy this book at Amazon. In this chapter you will learn to write fruitful functions. Speaking casually, they have no return value; more precisely, their return value is None. In this chapter, we are finally going to write fruitful functions.
The first example is area, which returns the area of a circle with the given radius: Sometimes it is useful to have multiple return statements, one in each branch of a conditional: As soon as a return statement runs, the function terminates without executing any subsequent statements.
Code that appears after a return statement, or any other place the flow of execution can never reach, is called dead code.
In a fruitful function, it is a good idea to ensure that every possible path through the program hits a return statement. If the flow of execution gets to the end of a function, the return value is None, which is not the absolute value of 0. To deal with increasingly complex programs, you might want to try a process called incremental development.
The goal of incremental development is to avoid long debugging sessions by adding and testing only a small amount of code at a time. As an example, suppose you want to find the distance between two points, given by the coordinates x1, y1 and x2, y2.
By the Pythagorean theorem, the distance is: In other words, what are the inputs parameters and what is the output return value? In this case, the inputs are two points, which you can represent using four numbers.
The return value is the distance represented by a floating-point value.
Immediately you can write an outline of the function: But it is syntactically correct, and it runs, which means that you can test it before you make it more complicated. To test the new function, call it with sample arguments: When testing a function, it is useful to know the right answer.
At this point we have confirmed that the function is syntactically correct, and we can start adding code to the body. The next version stores those values in temporary variables and prints them. If so, we know that the function is getting the right arguments and performing the first computation correctly.
If not, there are only a few lines to check. Next we compute the sum of squares of dx and dy: Finally, you can use math. Otherwise, you might want to print the value of result before the return statement. The print statements we wrote are useful for debugging, but once you get the function working, you should remove them.
Code like that is called scaffolding because it is helpful for building the program but is not part of the final product.
When you start out, you should add only a line or two of code at a time. As you gain more experience, you might find yourself writing and debugging bigger chunks.
Either way, incremental development can save you a lot of debugging time. The key aspects of the process are: Start with a working program and make small incremental changes. At any point, if there is an error, you should have a good idea where it is. Use variables to hold intermediate values so you can display and check them.
Once the program is working, you might want to remove some of the scaffolding or consolidate multiple statements into compound expressions, but only if it does not make the program difficult to read.
As an exercise, use incremental development to write a function called hypotenuse that returns the length of the hypotenuse of a right triangle given the lengths of the other two legs as arguments. Record each stage of the development process as you go. Assume that the center point is stored in the variables xc and yc, and the perimeter point is in xp and yp.
The first step is to find the radius of the circle, which is the distance between the two points. We just wrote a function, distance, that does that: Here is an example:The factorial of a negative number doesn’t exist. And the factorial of 0 is 1. You will learn to find the factorial of a number using recursion method in this example.
As i am new with TCL, So need some help.
|Scheme Macro Programming||Simple Report all non-const variables declared at namespace scope.|
|Java for Class X Computer Applications||Edit Please don't do this! You will find that MATLAB arrays either numeric or cell will let you do the same thing in a much faster, much more readable way.|
|C++ Program To Find Factorial||You will find that MATLAB arrays either numeric or cell will let you do the same thing in a much faster, much more readable way.|
|Write a C program to calculate factorial using recursion||The program goes as follows:|
Need to write a program for factorial, square-root, square, cube and cube-root of any given number (let it be 10). Without using the keys eg: sqrt. Thankyou. Factorial program in C programming language: C program to find and print factorial of a number, three methods are given, the first one uses for loop, the second uses a function to find factorial and the third uses iridis-photo-restoration.comial is represented using '!', so five factorial will be written as (5!), n factorial as (n!).
Write a program in the C programming language to find the factors or divisible of the inputted number. Make this program by using ‘ for loop ‘. It also tells the total number of factors of the inputted number.
Write a C program to find the factorial of the inputted number ; Write a C Program to check if the number is prime number or not ;. This program segment calculates the sum of integer numbers from 1 to n. Initially, the value of n is read from the keyboard and variable sum is initialized to zero.
C Program Using Structure to Calculate Marks of 10 Students in Different Subjects ; C Program Enter the Student Marks and Find the Percentage and Grade.