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Java's branching control uses the if-else structure (http://docs.oracle.com/javase/tutorial/java/nutsandbolts/if.html) for selecting which blocks of code should run. The if-statement by itself lets us choose whether or not to run a block of code: if ( boolExpr ) { // run these statements only if boolExpr was true; otherwise, skip. }
Making Selections. The “if” keyword is always followed by parentheses. The expression in the parentheses must evaluate to a boolean. The statement can be a single statement or a block. Safer as a block. if (booleanExpression) statement; if (booleanExpression) { statement(s); }
Flow of control through any given function is implemented with three basic types of control structures: Sequential: Default mode. Statements are executed line by line. Selection: Used for decisions, branching { choosing between 2 or more alternative paths. if - else. switch. conditional statements.
Using Selection: the CoinExample Class • if statement based on using a randomly generated number to represent a coin being flipped • The Java Math class random operation –Returns a random double >= 0.0 and < 1.0 • Use random number in if statement 10 double randomNumber = Math.random(); if (randomNumber < 0.5) {
4.4 Control Structures • Java has a sequence structure “built-in” • Java provides three selection structures – if – If…else – switch • Java provides three repetition structures – while – do…while – do • Each of these words is a Java keyword
1 Ιαν 2012 · In this chapter, we look at the main control structures in Java that enable selection and iteration. For selection, we cover “if-else,” “switch,” “break,” and “continue” statements, and the ternary operator. For iterating over code, we explore the “while,” “do-while,” and “for” loops.
4.4 Control Structures (Cont.) • Java has three kinds of control structures – Sequence statement, – Selection statements (three types) and – Repetition statements (three types) – All programs are composed of these control statements • Control-statement stacking – All control statements are single-entry/single-exit • Control ...
