main方法 4-6 When you give a class to the Java interpreter it looks for a main method in the class that has the prototype public static void main(String[]args) and begins executing the statements in it. Programming in Java JAVA
4-6 Programming in Java main 方法 • When you give a class to the Java interpreter it looks for a main method in the class that has the prototype public static void main(String[] args) and begins executing the statements in it
示俐：Circle calculator 4-7 程序构造一个称为circle的CircleCalculator 对象 。程序要求circle读入radius 程序要求circle计算area和circumference 程序要求circle显示radius,,area和 circumference Programming in Java JAVA
4-7 Programming in Java 示例：Circle calculator • 程序构造一个称为circle的 CircleCalculator 对象 • 程序要求circle 读入 radius • 程序要求circle 计算area 和 circumference • 程序要求circle 显示radius, area 和 circumference
CircleCalculatorRunner class 4-8 public class CircleCalculatorRunner f public static void main(String[]args) CircleCalculator circle new circleCalculator () construct send messages objec to circle.readInput () the circle object circle.doCalculations() circle.displayResults () Programming in Java JAVA
4-8 Programming in Java CircleCalculatorRunner class public class CircleCalculatorRunner { public static void main(String[] args) { CircleCalculator circle = new CircleCalculator(); circle.readInput(); circle.doCalculations(); circle.displayResults(); } } construct object send messages to the circle object
a2水 构造一个对象 4-9 new circleCalculator ( 调用这些语句 public CircleCalculator() { Statements } Programming in Java JAVA
4-9 Programming in Java 构造一个对象 new CircleCalculator() 调用这些语句 public CircleCalculator() { } Statements
CircleCalculator class 4-10 public class CircleCalculator data field { declarations private double radius; private double area; private double circumference; fill in constructor public CircleCalculator(){...} details public void readInput(){...} Pu void((. fill in method details Programming in Java JAVA
4-10 Programming in Java CircleCalculator class public class CircleCalculator { private double radius; private double area; private double circumference; public CircleCalculator() {...} public void readInput() {...} public void doCalculations() {...} public void displayResults() {...} } data field declarations fill in constructor details fill in method details