Process control and method

1. 1.   Assignment operator

public class _01 {
	public static void main(String[] arys){
		byte i=2;
		i+=3;
		i++;
		System.out.println(i);
		int a=10;
		a*=a+=1;
		a*=a+=1;
		System.out.println(a);
		
	}

1. 1.   String mosaics

   2. public class _02 {
      	public static void main(String[] args){
      		String string=" Give the green light to the plane i whether ";
      		int a = 100;
      		int b = 120;
      		System.out .println(a+b);
      		System.out .println("a+b="+a+b);
      		System.out .println(a+"+"+b+"="+(a+b));
      	}
      

2. 1. Ternary operator

1.   Process control

Different branches of the control program

1. 1.   Sequential structure

Strictly from top to bottom , From left to right

1. 1.   Branching structure

Through the specified judgment conditions , Selectively take different branches

1. 1. 1.  if...else...

      2. public class _04 {
         	public static void main(String[] args){
         		int  a= 100;
         		int b=11;
         		if(a>10){
         			System.out.println("1111");
         		}
         		else if(a>50){
         			System.out.println("2222");
         		}else if (a>100){
         			System.out.println("3333");
         		}
         		if(true)
         			System.out.println(" Execution completed ");
         	else 
         		System.out.println(" Execution completed ");
         	}

         public static void main(String[] args){
                 Scanner scanner =new Scanner(System.in);
                 
                 System.out.println(" Please enter a user name , And press enter to confirm ");
                 String username=scanner.next();
                 System.out.println(" Please input a password , And press enter to confirm ");
                 String password=scanner.next();
                 if(username.equals("admin")){
                     if(password.equals("root")){
                         System.out.println(" Landing successful ");
                     }else{
                         System.out.println(" Incorrect password ");
                     }
                 }else
                     System.out.println(" Incorrect user name , To register ");
                 
             }

1. 1. 1.  Switch

public class _08 {
	public static void main(String[] args) {
		char c = 'C';
		if (c == 'A' || c == 'B') {
			System.out.println(" good ");
		} else if (c == 'C') {
			System.out.println(" good ");
		}
		switch (c) {
		case 'A':
		case 'B':
			System.out.println(" good ");
			break;
		case 'C':
			System.out.println(" good ");
			break;
		}
	}

1. 1.   Loop structure

Repeat some code many times

1. 1. 1.  For
         1.   Single cycle

         2. public class _10 {public static void main(String[] args) {
            	for (int i = 0; i < 5; i++) {
            		System.out.println(i);
            	}
            	int i;
            	for ( i =0 ; i < args.length; i++) {
            		System.out.println(i);
            	}
            	System.out.println(i);
            }
            	

1. 1. 1. 1.   Nested loop

         2. public class _11 {
            	public static void main(String[] args) {
            		for (int i = 0; i < 5; i++) {
            			for (int j = 0; j < 5; j++) {
            				System.out.print(0+"  ");
            			}
            			System.out.println();
            		}
            	}
            

1. 1. 1.  While

      2. public static void main(String[] args){
         		int i=10;
         		while(i<100){
         			System.out.println(i);
         			i++;
         		}
         	}

1. 1. 1.  Do...while

• public static void main(String[] args){
  		int i=1000;
  		do{
  			System.out.println(i);
  			i++;
  		}while(i<100);
  			
  		
  	}

1. 1. 1.  Break&continue

• public static void main(String[] args) {
  	for (int i = 0; i < 10; i++) {
  		if (i == 3) {
  			break;
  		}
  		System.out.println(i);
  	}
  }public static void main(String[] args) {
  	for (int i = 0; i < 10; i++) {
  		if (i == 3) {
  			break;
  		}
  		System.out.println(i);
  	}
  }

  public static void main(String[] args) {
  		outerFor: for (int i = 0; i < 5; i++) {
  			for (int j = 0; j < 5; j++) {
  				if (j == 3) {
  					break outerFor;
  				}
  				System.out.print(j + "  ");
  			}
  			System.out.println();
  		}
  	}

 

1.   Method
   1.   summary

1. 1.   Method statement

 * Statement :

 *            List of modifiers   return type   Method name   ( parameter list ){ Method body }

 *

 *            List of modifiers :  There can be , There can be no , There can be multiple

 *                              Authority modification : public  protected private  Don't write   One out of four

 *                              Other modifications : static , synchronized

                                                     abstract , final A choice .....

                                                    

                  return type : 11 Any of several data types , If no return value is required , Then write void

                 

                  Method name : The name of the method , Look at the text and know the meaning , Hump nomenclature

                 

                  parameter list : One thing to do , Required prerequisites , Can be used as input parameter

                                   There can be multiple , use , commas such as int a , int b , int c....

                                  

                                   Shape parameter : At the time of method declaration , Defined parameter list

                                   Actual parameters : Method call , Actual incoming data

                                  

                  Method body : Code to execute

                          Be careful : return Terminate the method and return

                                   If there is a method with return value type , The method body must have return sentence

                                                     such as public static int m1(){

                                                             return 1;// there 1 As long as it is int value , Because the return value is int type

                                                     }

                                   If no return value Then you can write return Or not , Write it return Also cannot return data , Can only terminate the operation

                                            public static void m1(){

                                                     return; // Only the function of terminating method operation

                                            }

                                  

1. 1.   Methods classification

   2. public static void main(String[] args) {
      	int result =_19.m1(123,5312);
      	System.out.println(result);
      }
      public static int m1(int a , int b){
      	return a+b;
      }
      public static void m2(){
      	return ;
      }