This exercise contains points of knowledge:
Identifier, keyword, comment, variable, data type, constant

Basic data types:

• Integer type (int)
• Floating Point Type (float)
• Character type (char)
• Boolean type
  java provides a series of access controllers to set different levels of access based on class es, variables, methods (mothod), and construction methods.
  There are four main types of access rights for java:
• Default (default mode)
• Private (private mode)
• Public (public)
• Protected

Topic 1

• Write the code step by step as shown in the diagram:
  

• Write steps:

1. Define class Test1
2. Define main method
3. Console Output 5 Lines String Type Constant Value
4. Console Output 5 Line Character Type Constant Value

Answer:

public class Test1 {
    public static void main(String[] args) {

        // Console output any 5-line string type constant value
        System.out.println("Learning is like a spring-blossom");
        System.out.println("No increase,Day lengthens");
        System.out.println("");
        System.out.println("No damage,Loss in the year");
        System.out.println("Come on!juvenile");
         // Console output any 5-line character type constant value
        System.out.println('J');
        System.out.println('A');
        System.out.println('V');
        System.out.println('A');
        System.out.println('!');
  	}
}

Question 2

• Follow the `steps to write the code as shown in the diagram:

• Write steps:
  1. Define class Test2
  2. Define main method
  3. Console Output 5 Lines Integer Type Constant
  4. Console Output 5 Rows Decimal Type Constant Value

Reference Answer:

public class Test2 {
    public static void main(String[] args) {
        // Console output any 5-line integer type constant value
        System.out.println(-2147483648);
        System.out.println(-100);
        System.out.println(0);
        System.out.println(100);
        System.out.println(2147483647);

        // Console Output Any 5 Rows Decimal Type Constant Value
        System.out.println(-100.0);
        System.out.println(-10.0);
        System.out.println(0.0);
        System.out.println(10.9);
        System.out.println(100.9);

    }
}

Question 3

• Write the code step by step as shown in the diagram:

• Write steps:

  1. Define Class Test3
  2. Define main method
  3. Console Output All Boolean Type Constants

public class Test3 {
    public static void main(String[] args) {
        // Console Output All Boolean Type Constants
        System.out.println(true);
        System.out.println(false);
    }
}

Question 4

• Write the code step by step as shown in the diagram:

• 

• Write steps:

  1. Define Class Test4
  2. Define main method
  3. Define two byte type variables, assign the maximum and minimum values within the byte type range, and output to the console.
  4. Define two short type variables, assign values within the short type range, and output to the console.
  5. Define two variables of type int, assign values within the range of type int, and output them to the console.
  6. Define two long type variables, assign values that exceed the range of int type, and output them to the console.

Reference Answer:

public class Test4 {
    public static void main(String[] args) {
        // Define two byte type variables, assign the maximum and minimum values within the byte type range, and output to the console.
        byte num1 = -128;
        byte num2 = 127;
        System.out.println(num1);
        System.out.println(num2);

        // Define two short type variables, assign values within the short type range, and output to the console.
        short num3 = -32768;
        short num4 = 32767;
        System.out.println(num3);
        System.out.println(num4);
        
        // Define two variables of type int, assign values within the range of type int, and output them to the console.
        int num5 = -2147483648;
        int num6 = 2147483647;
        System.out.println(num5);
        System.out.println(num6);
        
        // Define two long type variables, assign values that exceed the range of int type, and output them to the console.
    	long num7 = -2147483649L;
    	long num8 = 2147483648L;
    	System.out.println(num7);
    	System.out.println(num8);
	}  
}

Topic 5

• Write the code step by step as shown:

• Write steps:
  1. Define Class Test5
  2. Define main method
  3. Define two float type variables, assign them to each other, and output them to the console.
  4. Define two variables of type double, assign values to each, and output them to the console.

Reference Answer:

public class Test5 {
      public static void main(String[] args) {
          // Define two float type variables, assign them to each other, and output them to the console.
          float num1 = -3.14F;
          float num2 = 3.14F;
          System.out.println(num1);
          System.out.println(num2);

          // Define two double s, assign values to each, and output to the console.
          double num3 = -3.4;
          double num4 = 3.4;
          System.out.println(num3);
          System.out.println(num4);
      }
  }

Sixth topic

• Write the code step by step as shown in the diagram:

• Write steps:

1. Define Class Test6
2. Define main method
3. Define five char type variables, assign values, and output to the console.
4. Define two boolean type variables, assign values to each, and output to the console.

Reference Answer:

public class Test6 {
    public static void main(String[] args) {
        // Define five char type variables, assign values, and output to the console.
        char ch1 = '9';
        char ch2 = 'J';
        char ch3 = 'a';
        char ch4 = ' ';
        char ch5 = '@';

        System.out.println(ch1);
        System.out.println(ch2);
        System.out.println(ch3);
        System.out.println(ch4);
        System.out.println(ch5);
        // Define two boolean type variables, assign values to each, and output to the console.
      	boolean b1 = true;
      	boolean b2 = false;

      	System.out.println(b1);
      	System.out.println(b2);
  	}
 }

Topic 7

• Write the code step by step as shown in the diagram:

• 

• Step illustrations:
  

• Development Tip: Define the format in which variables are not assigned
  // Data type variable name;
  int temp；

• Write steps:

  1. Define Class Test7
  2. Define main method
  3. Define and assign two integer variables a, b
  4. Console Output Variables a, b Before Interchange
  5. Define a third-party variable temp, no assignment
  6. Use third-party variable temp to exchange values of a and b
  7. Console Output Variable a, b Interchangeable Value

Reference Answer:

class Test7{
	public static void main(String[] args){
	
		int a = 10;
		int b = 20 ;
		System.out.println("Before interchange");
		System.out.println("a =" + a);
		System.out.println("b= " + b);
		int temp;
		temp = a;
		a = b;
		b = temp;
		
		System.out.println("After interchange");
		System.out.println("a = " + a);
		System.out.println("b = "+b);
	
	}

}

Extended title:

Question 8

• Write the code step by step as shown in the diagram:

• Development Tip: Symbols for Four Operations
  Plus: +
  Subtraction: -
  Multiply: *
  Except: /
• Write steps:
  1. Define Class Test8
  2. Define main method
  3. Defines two variables of type int, x and y, with x assigned to 100 and Y assigned to 200
  4. Define a new variable add, save the sum of variables x, y, and print to the console
  5. Define a new variable sub, save the difference between the variables x and y, and print to the console
  6. Define a new variable mul, save the product of variables x, y, and print to the console
  7. Define a new variable div, save the quotient of the variables x, y, and print it to the console

Reference Answer:

class Test8{

	public static void main(String[] args){
	
		int x = 100;
		int y = 200;
		int add = x + y;
		int sub  = y - x;
		int mul = x * y;
		int div  = x / y;
		System.out.println("x,y And for: " + add);
		System.out.println("x,y The difference is: " + sub);
		System.out.println("x,y The product of is: " + mul);
		System.out.println("x,y Business for: " + div);
	
	}

}

Item 9

• Write the code step by step as shown in the diagram:

• 

• Development Tip: Observe the results of numeric operations of decimal type.
  Decimal operations often suffer from loss of precision, so it is not recommended to use basic types of operations.

• Write steps:

  1. Define class Test9
  2. Define main method
  3. Defines two double type variables x, y, with X assigned to 100.8 and Y assigned to 20.6
  4. Define a new variable add, save the sum of variables x, y, and print to the console
  5. Define a new variable sub, save the difference between the variables x and y, and print to the console
  6. Define a new variable mul, save the product of variables x, y, and print to the console
  7. Define a new variable div, save the quotient of the variables x, y, and print it to the console

• Tips:

  1. Addition: +
  2. Subtraction: -
  3. Multiplication: *
  4. Division: /

Reference Answer:

public class Test9 {
    public static void main(String[] args) {

//       Define two variables of type double x,y and assign any value.
        double x = 100.8;
        double y = 20.6;
        
//       Define new variables, save the sum of variables x,y, and print to the console
        double add = x + y;
        System.out.println("x,y And for:");
        System.out.println(add);
        
//       Define a new variable, save the difference between the variables X and y, and print to the console
        double sub = x - y;
        System.out.println("x,y The difference is:");
        System.out.println(sub);
        
//       Define a new variable, save the product of the variables x,y, and print to the console
        double mul = x * y;
        System.out.println("x,y The product of is:");
        System.out.println(mul);
        
//       Define a new variable, save the quotient of the variable x,y, and print to the console
        double div = x / y;
        System.out.println("x,y Business:");
        System.out.println(div);
    }
}

Topic 10

• Write the code step by step as shown in the diagram:

• 

• Development Tip: Output without line breaks
  System.out.print("integer type-byte:"); //remove ln, no line break after output
  System.out.println(10); //with ln, with line breaks after output

• Write steps:

  1. Define class Test10
  2. Define main method
  3. Define a byte type variable and assign it a value of 10. Wrap the output type description and output the variable value.
  4. Define a short type variable and assign it a value of 100, no line break output type description, line break output variable value.
  5. Defines an int type variable and assigns it a value of 1000, no line break output type description, and line break output variable value.
  6. Define a long type variable and assign it a value of 10000, no line break output type description, line break output variable value.
  7. Define float type variable and assign it to 100000.0, no line break output type description, line break output variable value.
  8. Defines a double type variable and assigns it to 1000000.0, no line break output type description, line break output variable value.
  9. Define a char type variable and assign it a value of'Z', no line break output type description, line break output variable value.
  10. Defines a boolean type variable and assigns it false, does not wrap the output type description, and wraps the output variable value.

Reference Answer:

public class Test10 {
    public static void main(String[] args) {
        // Define Variables
        byte b = 10;
        // Output string without wrapping
        System.out.print("Integer type-byte:");
        // Line Break Output Variable Value
        System.out.println(b);      
        
        short s = 100;
      	System.out.print("Integer type-short:");
      	System.out.println(s);
        
        int i = 1000;
    	System.out.print("Integer type-int:");
    	System.out.println(i);

        
    	long l = 10000;
    	System.out.print("Integer type-long:");
    	System.out.println(l);
 
    	float f = 100000.0F;
  		System.out.print("Decimal Type-float:");
  		System.out.println(f);
        
        	double d = 1000000.0;
		System.out.print("Decimal Type-double:");
		System.out.println(d);
		char c = 'Z';
		System.out.print("Character type-char:");
		System.out.println(c);
		
         boolean bo = false;
		System.out.print("Boolean type-boolean:");
		System.out.println(bo);
  	}
}