沈阳工业大学软件学院Java程序设计课件 第3章.ppt

第三章 类的方法;目录;3.1 方法的控制流程;3.1.1 if选择结构;3.1.1 if选择结构(续);ex3_1 输入一个年份，判断它是不是闰年。 闰年: 能被4整除但不能被100整除，或者能被400整除。 public class ex3_1 { public static void main(String[ ] args) throws IOException{ int year; boolean IsLeapYear; System.out.println(Enter the year:); BufferedReader in =new BufferedReader( new InputStreamReader(System.in)); year=(new Integer(in.readLine())).intValue(); ; IsLeapYear=((year%4==0 year%100 != 0)||(year%400 == 0)); if (IsLeapYear) { System.out.print(year); System.out.println( is a leap year); } else { System.out.print(year); System.out.println( is not a leap year); } } };输入两个整数比较大小 import java.io.*; public class ex3_2 { public static void main(String[ ] args)throws IOException { int x,y; BufferedReader in = new BufferedReader( new InputStreamReader(System.in)); System.out.println(Enter x and y:); x=(new Integer(in.readLine())).intValue(); y=(new Integer(in.readLine())).intValue(); if (x!=y) if (xy) System.out.println(xy); else System.out.println(xy); else System.out.println(x=y); } } ;例子: If (ab) System.out.println(The larger one is: +a); else System.out.println(The larger one is: +b); 用条件运算符重写: System.out.println(The larger one is: + (ab)?a:b); ;计算每个月的天数 static int daysInMonth(int month) { if (month == 2) return(28); else if ((month==4)||(month==6)||(month==9)||(month==11)) return(30); else return(31); };已知一个学生的分数，给出其分数等级。90-100分为Ａ级；80-89分为B级；70-79分为Ｃ级；60-69分为D级；0-59分为E级 public class IfElseDemo { public static void main(String[] args) { int testscore = 76; char grade; if (testscore = 90) { grade = A; } else if (testscore = 80) { grade = B; } else if (testscore = 70) { grade = C; } else if (testscore = 60) { grade = D; } else {