方法:
命名的代码块
方便重复调用
减少重复代码
public class Test1 {
public static void main(String[] args) {
System.out.println(1);
f();
System.out.println(2);
f();
System.out.println(3);
f();
}
private static void f() {
System.out.println(4);
System.out.println(5);
}
}
方法的参数
Static void f(int a){}
f(3)
package day0301;
public class Test2 {
public static void main(String[] args) {
System.out.println(1);
f(2);
System.out.println(3);
f(4);
System.out.println(5);
f(6);
}
private static void f(int i) {
System.out.println(i*i);
}
}
流程控制
If
Switch
For
While
Do…while
If
If(条件){代码}
package day0302;
import java.util.Scanner;
public class Test1 {
public static void main(String[] args) {
/**
* 输入号码:
* 以4结尾 免费
* 8结尾 80
* 其他 30
*/
System.out.print("请输入号码:");
String tel = new Scanner(System.in).nextLine();
f(tel);
}
private static void f(String tel) {
if(tel.length() != 11){
System.out.println("号码不正确");
return;
}
if(tel.endsWith("4"))
{
System.out.println("免费");
}else if(tel.endsWith("8")){
System.out.println(80);
} else {
System.out.println(30);
}
}
}
个人所得税
package day0303;
import java.util.Scanner;
public class Test1 {
public static void main(String[] args) {
System.out.print("输入税前工资:");
double v = new Scanner(System.in).nextDouble();
f(v);
}
private static void f(double v) {
if (v <= 5000) {
System.out.println("不用交税");
return;
}
v -= 5000;
double r;
int k;
if (v <= 3000) {
r = 0.03;
k = 0;
} else if (v > 3000 && v <= 12000) {
r = 0.1;
k = 210;
} else if (v > 12000 && v <= 25000) {
r = 0.2;
k = 1410;
} else if (v > 25000 && v <= 35000) {
r = 0.25;
k = 2660;
} else if (v > 35000 && v <= 55000) {
r = 0.3;
k = 4410;
} else if (v > 55000 && v <= 80000) {
r = 0.35;
k = 7160;
} else {
r = 0.45;
k = 15160;
}
System.out.println("应交税:" + (v * r - k));
}
}