各章节AP计算机科学知识点梳理（上）

　　计算机作为当前最被看好的一大专业领域，很多同学们在AP课程学习期间会选修AP计算机科学这门课来帮助自己打好知识基础。今天A+国际教育小编就带大家梳理一下各章节中AP计算机知识点内容，来帮助同学们更为系统地开展AP计算机科学的学习和备考工作。

　　1. Introductory Java Language Features

　　Package And Classes 类和包

　　public class FirstProg // file name is FirstProg.java { public static type1 method1 (parameter list) {} public static type2 method2 (parameter list) {} ...... public static void main (String[] args) {} }

　　All java methods must be contained in a class; all program statement must be placed in a method

　　The class that contains the main method does not contain many additional methods.

　　reserved words (Keywords): class, public, static, void, main.

　　public: the class or method is usable outside of the class

　　static: methods that will not access any objects of a class. The main method must always be static.

　　Types And Identifiers 标识符和类型

　　Identifiers 标识符

　　Identifier: name for a variable, parameter, constant, user-defined method, user-defined class

　　cannot begin with a digit

　　Lowercase: for variables and methods

　　Uppercase: separate into multiple words e.g getName, findSurfaceArea

　　a class name starts with a capitol letter

　　Built-in Types 内置类型

　　int - 整数 boolean - true or false double - 小数

　　Storage of Numbers 数值储存

　　Integers 整数 binary Integer.MAX_VALUE == 2^31-1 Integer.MIN_VALUE == - 2^31 Floating-Point Numbers 浮点数 float & double

　　sign * mantissa * 2^exponent

　　round-off error - when floating-point numbers are converted into binary, most cannot be represented exactly

　　e.g 0.1*26 ≠ 0.1+0.1......(26 terms)

　　NaN"not a number" - undefined number

　　Hexadecimal Numbers 十六进制数

　　conversion between hex and binary 5 hex = 0101 bin         F hex = 1111 bin 5F hex = 01011111 bin

　　Final Variable  Final变量

　　user-defined constant

　　keyword final

　　e.g.   final double TAX_RATE = 0.08;

　　final variable can be declared without initializing it immediately, but can only be given just once

　　array bound

　　final int MAXSTUDENTS = 25;

　　int [] classList = new Int[MAXSTUDENTS];

　　Operators 运算符

　　Arithmetic Operators 算数运算符

　　+ addition   - subtraction   * multiplication   /devision   %mod(remainder)

　　Relational Operators 关系运算符

　　== equal to   != not equal to   > greater than   < less than   >= greater or equal to   <= less than or equal to

　　Relational Operators can only be used in comparison of primitive types.

　　User defined types : equals, compareTo  methods

　　floating-point should not be compared directly using relational operators.

　　Logical Operators 逻辑运算符

　　! NOT   && AND   || OR Short-circuit evaluation evaluated from left to right evaluation automatically stops as soon as the value of the entire expression is known

　　Assignment Operators 赋值运算符

　　Compound assignment operators : =      +=      -=      *=      /=      %=

　　Increment and Decrement Operator 递增递减运算符

　　++      --

　　Operator Precedence 运算符的优先级

　　!, ++ , --                                          right to left

　　* , / , %                                           left to right + , -                                                 left to right <,>, <=,>=                                    left to right == , !=                                            left to right && || =, +=, -+, *=, /=, %=                    right to left

　　Input/Output 输入输出

　　Escape sequences 转义字符

　　\n      newline \"      double quot \\       backslash

　　Control Structures 控制结构

　　Decision-Making Control Structures 条件结构

　　if...

　　if...else...

　　nested if

　　extended if (if...elseif...)

　　Iteration 循环结构

　　for loop

　　for (initialization; termination condition; update statement)

　　The termination condition is tested at the top of the loop

　　the update statement is performed at the bottom

　　loop variable should not have its value changed inside the loop body

　　the scope of the loop variable can be restricted to the loop body by combining the loop variable declaration with the initialization.

　　for-each loop

　　for (SomeType element : collection)

　　cannot be used to replace or remove elements

　　hides the index variable that is used with array

　　while loop

　　while (boolean test)

以上就是A+国际教育小编关于部分AP计算机科学知识点内容的梳理，当然由于篇幅有限，小编只更新了部分内容，其余部分将在接下来几天中列举。欢迎持续关注哟！