Java零基础入门：运算符练习

之前练习的库存：

public class Test01 {    public static void main(String[] args) { int x = 10; int a = x + x++;//a=10+10，该代码执行结束，x=11; //++X:先自加再取值，X++先取值再自加 //a先取x+x的值，x再自加值 System.out.println("x="+a);//20 System.out.println("x="+x);//11 int b = x+ ++x;//b=11+12,该代码执行结束，x=12; System.out.println("b="+b);//23 System.out.println("x="+x);//12 int c = x + x--;//c=12+12,该代码执行结束，x=11 System.out.println("c="+c);//24 System.out.println("x="+x);//11 int d = x + --x;//d=11+10,该代码执行结束，x=10 System.out.println("d="+d);//21 System.out.println("x="+x);//10    }}

public class Test02 {    public static void main(String[] args){ int a = 15; int b = 2; double c = 2; System.out.println(a+"/"+b+"="+(a/b)); System.out.println(a+"%"+b+"="+(a%b)); System.out.println(a+"/"+c+"="+(a/c)); System.out.println(a+"%"+b+"="+(a%b));    }}

public class ZuoyeTest03 {     public static void main(String[] ages){  boolean x,y,z;  int a = 15;  int b = 2;  x = a > b;  y = a < b;  z = a != b;  System.out.println("x="+x);  System.out.println("y="+y);  System.out.println("z="+z);     }}

public class Test04 {    public static void main(String[] args){ boolean raining = false; if(raining){     System.out.println("外面下雨了，出门记得带一把伞哦！"); }else{     System.out.println("天气不错哦！"); } boolean eatFull = true; if(eatFull){     System.out.println("吃的好饱啊！"); }else{     System.out.println("还没有吃饱，再来份米饭！"); } boolean sex = true; if(sex){     System.out.println("男");     System.out.println("Hello world!"); } else{     System.out.println("女"); } java.util.Scanner scan = new java.util.Scanner(System.in); System.out.print("请输入数字；"); int i = scan.nextInt(); if(i==1){     System.out.println("性别：男"); }else if(i==0){     System.out.println("性别：女"); }else{     System.out.println("对不起，你输入不合法！"); } System.out.print("输入考试成绩："); int score = scan.nextInt(); String grade = "大笨蛋"; if(score < 0 || score > 100){     grade = "对不起，您输入的成绩不合法！"; }else if(score >= 90){     grade = "优秀"; }else if(score >= 80){     grade = "良好"; }else if(score >= 70){     grade = "中等"; }else if(score >= 60){     grade = "及格"; } System.out.println("成绩等级：" + grade);    }}

public class Test05 {    public static void main(String[] args){ java.util.Scanner scann = new java.util.Scanner(System.in); System.out.print("请输入天气指数，1 表示下雨天，0 表示晴天："); int weather = scann.nextInt(); if(weather == 1){     System.out.print("请再输入您的性别，1 表示男，0 表示女：");     int sex = scann.nextInt();     if(sex == 0){  System.out.println("女士，外面下雨了，您需要带一把小花伞");     }else if(sex == 1){  System.out.println("哥们，外面下雨了，您需要带一把大黑伞");     }else{  System.out.println("对不起，您输入性别参数出错了！");     } }else if(weather == 0){     System.out.println("走起，一起出去玩耍喽！"); }else{     System.out.println("对不起，您输入天气参数出错了！"); }    }}

public class homework01 {    public static void main(String[] args){ int i = 5; int j = 5; int m = 5; int n = 5; i++;//i=5,该代码执行结束后，i=6; j = j + 1;//j=6 m--;//m=5,该代码执行结束之后，m=4; n = n - 1;//n=4; System.out.println(i);//i=6 System.out.println(i++);//i=6,该代码执行结束后，i=7 System.out.println(++i);//i=8,该代码执行结束后，i=8 System.out.println(i--);//i=8,该代码执行结束后，i=7 System.out.println(); System.out.println(j); System.out.println(j++); System.out.println(j--); System.out.println(--j); System.out.println(); System.out.println(m); System.out.println(n);    }}

public class homework02 {    public static void main(String[] args) { for (int i = 10; i > 0; i--) {     System.out.println("i = " + i); } System.out.println("-------------分割线---------------"); for (int i = 10; i > 0; i -= 2) {     System.out.println("i = " + i); } System.out.println("-------------分割线---------------"); for (int i = 100; i >= 10; i /= 3) {     System.out.println("i = " + i); }    }}

public class homework04 {    public static void main(String[] args){ for(int i = 1;i <= 5; i++){     System.out.print("i = " + i + ","); } System.out.println();  for(int j=1;j<=2;j++){      System.out.print("j="+j+",");  }  System.out.println();  for(int j = 1;j <= 2;j++){      for(int i = 1;i <= 5;i++){   System.out.print("i="+i+",");      }  }    }}

public class homeword5 {    public static void main(String[] args){ for(int i = 1;i <= 9;i++) { //外层循环，负责9行     for(int j = 1;j <= i;j++) {//内部循环，负责输出当前  System.out.print(i+"*"+j+"="+i*j+" ");     }     System.out.println(); }    }}