As you may already know, in sequence control structures statements are executed sequentially, in the same order in which they appear in the program. However, in serious programming, rarely do you want the statements to be executed sequentially. Many times you want a block of statements to be executed in one situation and an entirely different block of statements to be executed in another situation. This is where a decision control structure can take action!
A decision control structure evaluates a Boolean expression or a set of Boolean expressions and then decides which block of statements to execute.