Chapter Summary

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The main topic of this chapter has been program control. C offers you many aids for structuring your programs. The while and the for statements provide entry-condition loops . The for statements are particularly suited for loops that involve initialization and updating. The comma operator enables you to initialize and update more than one variable in a for loop. For the rare occasion when an exit-condition loop is needed, C has the do while statement.

All these loops use a test condition to determine whether another loop cycle is to be executed. In general, the loop continues if the test expression evaluates to a nonzero value, and terminates otherwise . Often, the test condition is a relational expression, which is an expression formed by using a relational operator. Such an expression has a value of 1 if the relation is true and a value of otherwise.

In addition to relational operators, this chapter looked at several of C's arithmetic assignment operators, such as += and *= . These operators modify the value of the left-hand operand by performing an arithmetic operation on it.

Arrays were the next subject. Arrays are declared in the same fashion as ordinary variables , but they have a number enclosed in brackets to indicate the number of elements. The first element of an array is numbered 0; the second is numbered 1, and so forth. The subscripts used to number arrays can be manipulated conveniently by using loops.

Finally, the chapter showed how to write and use a function with a return value.

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