From scratch learn Java-5. Use conditional test for judgment, learn java-5

Source: Internet
Author: User

From scratch learn Java-5. Use conditional test for judgment, learn java-5

1. Use the if statement to test the most basic conditions;
2. test whether a value is greater than or less than another value;
3. test whether the two values are equal;
4. Use the else statement corresponding to the if statement;
5. Combine multiple conditions for testing;
6. Use the switch statement to perform complex condition tests;
7. Create a test using the ternary operator;

 

Program Game: Preliminary use of if Statements

 1 package com.jsample; 2  3 public class Game { 4     public static void main(String[] args){ 5         int total = 0; 6         int score = 7; 7         if(score == 7){ 8             System.out.println("You score a touchdown!"); 9         }10         if(score == 3){11             System.out.println("You kick a field goal!");12         }13         total = total + score;14         System.out.println("Total score: " + total);15     }16 }
View Code

 

Output:

You score a touchdown!
Total score: 7

 

Program Commodity: Use the switch statement to buy or sell things

1 package com. jsample; 2 3 public class Commmodity {4 public static void main (String [] args) {5 String command = "BUY "; // The command is set to "BUY" 6 int balance = 550; 7 int quantity = 42; 8 9 switch (command) {10 case "BUY": 11 quantity + = 5; 12 balance-= 20; 13 break; 14 case "Limit": 15 quantity-= 5; 16 balance + = 15; 17} 18 System. out. println ("Balance:" + balance + "\ n" 19 + "Quantity:" + quantity); 20} 21}
View Code

 

Output:

Balance: 530
Quantity: 47

 

Program Clock: uses the built-in timing function of Java to track the current date and time, and displays the information in one sentence

1 package com. jsample; 2 3 import java. time. *; // enable the program to use the java class. time. localDateTime, which is used to track the current date and time 4 import java. time. temporal. *; // enables the program to use java. time. temporalfield. chronoField 5 6 public class Clock {// start the Clock program and its main () Statement Block 7 public static void main (String [] args) {8 // get current time and date 9 LocalDateTime now = LocalDateTime. now (); // create a LocalDateTime object named now, which contains the current date and time of the system 10 int hour = now. get (Chron OField. HOUR_OF_DAY); // create the variables hour, month, day, year. The values of these variables come from the LocalDateTime object 11 int minute = now. get (ChronoField. MINUTE_OF_HOUR); 12 int month = now. get (ChronoField. MONTH_OF_YEAR); 13 int day = now. get (ChronoField. DAY_OF_MONTH); 14 int year = now. get (ChronoField. YEAR); 15 16 // display greeting17 if (hour <12) {// display one of the three greetings. The displayed content depends on the value of the hour variable 18 System. out. println ("Good morning. \ n "); 19} else if (hour <17) {20 then E M. out. println ("Good afternoon. \ n "); 21} else {22 System. out. println ("Good evening"); 23} 24 25 // begin time message by showing the minutes26 System. out. print ("It's"); // display the specific number of minutes based on the value of the minute variable 27 if (minute! = 0) {28 System. out. print ("" + minute + ""); 29 System. out. print (minute! = 1 )? "Minutes": "minute"); 30 System. out. print ("past"); 31} 32 33 // display the hour34 System. out. print (""); // display the hour value in the 12-hour System 35. out. print (hour> 12 )? (Hour-12): hour); 36 System. out. print ("o 'clock on"); 37 38 // display the name of the month39 switch (month) {// display different month names based on the value of the variable month 40 case 1: System. out. print ("January"); break; 41 case 2: System. out. print ("February"); break; 42 case 3: System. out. print ("March"); break; 43 case 4: System. out. print ("CMDL"); break; 44 case 5: System. out. print ("May"); break; 45 case 6: System. out. print ("June"); break; 46 case 7: System. out. print ("July"); break; 47 case 8: System. out. print ("August"); break; 48 case 9: System. out. print ("September"); break; 49 case 10: System. out. print ("October"); break; 50 case 11: System. out. print ("November"); break; 51 case 12: System. out. print ("December"); break; 52} 53 54 // display the date and year55 System. out. println ("" + day + "," + year + ". "); // display the current date and year 56} // end main () Statement block 57} // end the entire clock Program
View Code

 

Output:

Good morning.

It's 15 minutes past 9 o 'clock on March 16,2018.

 

Program GradeGame: stores user input scores (0-100), automatically grades and outputs comments (Implemented Using if and switch statements respectively)

 1 package com.jsample; 2  3 public class GradeGame { 4     public static void main(String[] args){ 5         int grade = Integer.parseInt(args[0]); 6         char gpa = 'E'; 7  8         if (grade > 80) 9         {10             System.out.println("A:Perfect");11             gpa = 'A';12         }13         else if (grade > 60)14         {15             System.out.println("B Good");16             gpa = 'B';17         }18         else if (grade > 40)19         {20             System.out.println("C Not bad");21             gpa = 'C';22         }23         else if (grade > 20)24         {25             System.out.println("D You still have lots more to work on");26             gpa = 'D';27         }28         else29         {30             System.out.println("F Not even wrong");31             gpa = 'F';32         }33 34         switch (gpa){35             case 'A':System.out.println("A:Perfect");break;36             case 'B':System.out.println("B Good");break;37             case 'C':System.out.println("C Not bad");break;38             case 'D':System.out.println("D You still have lots more to work on");break;39             case 'F':System.out.println("F Not even wrong");break;40             default:System.out.println("Who's your daddy");break;41         }42     }43 }
View Code

 

Input:

65

Output:

B Good
B Good

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.