Java课件_LESSON 3 - Operators and Control Structures.pptVIP

LESSON 3: Operators and Control Structures 吴砥 wudi@ Department of Electronics Information Engineering, Huazhong University of Science Technology, Wuhan, P.R.C. Outline Operators Control structures Summary Operators Five basic arithmetic operators Sample code Assignment operator Sample code Rules of operator precedence (, ) *, /, % +, - Sample code Increment decrement x++ postincrement ++x preincrement y-- postdecrement --y predecrement Sample code Equality operators == != Relational operators = = Sample code Logical operators , |, || ! ^ Logical operators - AND , The expression will be true only if both operands tests are also true. Sample code Logical operators - OR ||, | The expression will be false only if both operands tests are also false. Sample code Logical operators - NOT ! The value of the NOT expression is the negation of the expression. Sample code Logical operators – XOR ^ The expression will return true only if its operands are different. Bitwise operators The bitwise operators in Java are all inherited from C and C++ and are used to perform operations on individual bits in integers. Sample code Bitwise logical Sample code Ternary Operator ? : maxAandB = a b ? a : b Sample code Control Structures No goto The finger of blame was pointed at the goto statement The notion of so-called structured programming became almost synonymous with “goto elimination” Java does not have a goto statement; however, goto is a reserved word and should not be used in a Java program Sequence structure The sequence structure is built into Java. Unless directed otherwise, the computer executes Java statements one after the other in the order in which they are written. Java keywords The if selection structure The brackets are optional when the body only includes one single statement. The body can be block. Nested if Sample code Multiple selection structure Sometimes switch is a better choice than if/else switch multiple selection structure can handle a series of dec