4th Loop Structure Overview and the format of the for statement and its use

04.01_java Language Basics (circular structure overview and for statement formats and their use)

• A: Classification of cyclic structures
  • For,while,do...while
• B: Loop structure for statement format:

• for(初始化表达式;条件表达式;循环后的操作表达式) {    循环体;    }    

• C Execution Process:
  • A: Execute initialization statement
  • B: Execute a JUDGMENT condition statement to see if its return value is TRUE or False
    • If true, continue execution
    • If False, the loop is ended
  • C: Execute the loop body statement;
  • D: An action expression after the loop is executed
  • E: Go back to B.
• D: Case Demo
  • Output 10 times "HelloWorld" in the console

04.02_java Language Basics (the practice of looping structures for statements get data)

• A: Case Demo
  • Requirements: Please output data in the console 1-10
  • Requirements: Please output data in the console 10-1
• B: Precautions
  • A: Determines whether a conditional statement is a Boolean type, either simple or complex.
  • B: Loop body statement If it is a statement, the curly braces can be omitted, and in the case of multiple statements, the curly braces cannot be omitted. Never omit the suggestion.
  • C: Generally speaking: there is no semicolon on the left curly brace, there is no left brace for the semicolon

04.03_java Language Foundation (the summation idea of the practice of circular structure for statement)

• A: Case Demo
  • Requirements: Finding the sum of data between 1-10
• B: Student Practice
  • Requirements: Find the number of even numbers between 1-100 and
  • Requirements: Find out between 1-100 odd and

04.04_java Language Foundation (cyclic structure for statement of practice Narcissus)

• A: Case Demo

  • Requirements: Output All "daffodils" on the console

  • The so-called Narcissus number refers to a three-digit number whose numbers are cubic and equal to the number itself.

  • Example: 153 is a number of daffodils.
  • 153 = 111 + 555 + 333 = 1 + 125 + 27 = 153

04.05_java Language Foundation (statistical idea of the practice of circular structure for statements)

• A: Case Demo
  • Requirements: Statistics of "narcissus number" total number of

04.06_java Language Foundation (format and basic use of the loop structure while statement)

• A: The format of the loop structure while statement:

• while循环的基本格式：    while(判断条件语句) {    循环体语句;    }    完整格式：    初始化语句;    while(判断条件语句) {    循环体语句;    控制条件语句;    }    

• B: Execution Process:
  • A: Execute initialization statement
  • B: Execute a JUDGMENT condition statement to see if its return value is TRUE or False
    • If true, continue execution
    • If False, the loop is ended
  • C: Execute the loop body statement;
  • D: Execute control condition statement
  • E: Go back to B.
• C: Case Demo
  • Requirements: Please output data in the console 1-10

04.07_java Language Foundation (practice of loop structure while statement)

• A: Summation thought
  • The sum of 1-100
• B: Statistical Ideas
  • Count the number of daffodils.

04.08_java Language Basics (format and basic use of circular structure do...while statements)

• A: The format of the circular structure Do...while statement:

• do {    循环体语句;    }while(判断条件语句);    完整格式；    初始化语句;    do {    循环体语句;    控制条件语句;    }while(判断条件语句);    

• B: Execution Process:
  • A: Execute initialization statement
  • B: Execute the loop body statement;
  • C: Execute control condition statement
  • D: Execute a Judgment condition statement to see if its return value is TRUE or False
    • If true, continue execution
    • If False, the loop is ended
  • E: Go back to B.
• C: Case Demo
  • Requirements: Please output data in the console 1-10

04.09_java Language Foundation (the difference between circular structures of three circular statements)

• A: Case Demo
  • The difference between the three circular statements:
  • The Do...while loop executes at least one loop body.
  • The For,while cycle must first determine whether the condition is true, and then decide whether to execute the Loop body statement.
• B: Case Demo
  • The difference between a for loop and a while loop:
    • A: If you want to continue using the variable that controls the condition after the loop is over, use the while loop, otherwise use the For loop. I don't know who to use for loop. Because variables disappear early from memory, you can improve the efficiency of memory usage.

04.10_java Language Foundation (cycle of circular structure considerations)

• A: Must pay attention to control the condition statement control the problem of the variable, do not lose, otherwise it is easy to die cycle.
• B: Two of the simplest dead loop formats
  • while (true) {...}
  • for (;;) {...}

04.11_java Language Foundation (loop structure loop nesting output 4 rows 5 columns of stars)

• A: Case Demo

  • Requirements: Please output a 4-row, 5-column star (*) pattern.

  •         *****        *****        *****        *****        注意：        System.out.println("*");和System.out.print("*");的区别        

• B: Conclusion:
  • Outer loop control number of rows, inner loop control number of columns

04.12_java Language Foundation (cyclic structure loop nested output positive triangles)

• A: Case Demo

• 需求：请输出下列的形状    *    **    ***    ****    *****    

04.13_java Language Foundation (Loop structure 99 multiplication table)

• A: Case Demo
  • Requirements: Output 99 multiplication table on the console.
• B: Code optimization

• 注意：    ‘\x‘ x表示任意，\是转义符号,这种做法叫转移字符。    ‘\t‘    tab键的位置    ‘\r‘    回车    ‘\n‘    换行    ‘\"‘    ‘\‘‘    

04.14_java language Base (Control jump statement break statement)

• A:break Usage Scenarios
  • Only in Switch and loop

04.15_java language Base (Control jump statement continue statement)

• A:continue Usage Scenarios
  • Only in the loop

04.16_java Language Basics (Control of jump statement labels)

• Label: Mark a loop to control it
• Label composition rule: is actually a valid identifier

04.17_java Language Basics (Control adjustment statement exercises)

• A: Exercises

• for(int x=1; x<=10; x++) {    if(x%3==0) {    //在此处填写代码    }    System.out.println(“Java基础班”);    }    我想在控制台输出2次:“Java基础班“    我想在控制台输出7次:“Java基础班“    我想在控制台输出13次:“Java基础班“    

04.18_java language Base (Control jump statement return statement)

• The role of A:return
  • Return
  • In fact, its function is not to end the loop, but to end the method.
• B: Case Demo
  • What is the difference between return and break and continue?
  • Return is the End method
  • Break is jumping out of the loop
  • Continue is to terminate this cycle and continue the next cycle.

04.19_java Language Basics (Method overview and format description)

• A: Why should there be a way
  • Improve Code reusability
• B: What is a method
  • A block of code that completes a specific function.
• C: Format of the method

• 修饰符 返回值类型 方法名(参数类型 参数名1,参数类型 参数名2...) {    方法体语句;    return 返回值;    }    

• D: Format description of the method
  • Modifier: Use public static now. We'll explain the other modifiers in more detail later.
  • Return value type: is the data type of the functional result.
  • Method Name: Conforms to the naming convention. Convenient for our call.
  • Parameters:
    • Actual parameters: is actually involved in the operation.
    • The formal parameter is the method definition that is used to receive the actual parameter.
  • Parameter type: is the data type of the parameter
  • Parameter name: The name of the variable
  • Method Body Statement: Is the code that completes the function.
  • Return: the End method.
  • Return value: Is the result of the function, which is brought to the caller by return.

04.20_java Language Foundation (method summation case and its invocation)

• A: How to write a method
  • 1, explicit return value type
  • 2, clear parameter list
• B: Case Demo
  • Requirements: two cases of data
• C: Method Invocation Plot

04.21_java Language Basics (Method Considerations)

• A: Method invocation (with a specific return value)
  • A: Call alone, generally no meaning, so not recommended.
  • B: The output is called, but not good enough. Because we may need to do further work on the results.
  • C: Assignment invocation, recommended scenario.
• B: Case Demo
  • A: Method does not call do not execute
  • B: Methods and methods are lateral relationships, cannot be nested defined
  • C: When the method is defined, the arguments are separated by commas
  • D: Do not pass the data type at the time of method invocation
  • E: If the method has a definite return value, be sure to have return with a value

04.22_java Language Basics (practice of methods)

• A: Case Demo
  • Requirements: Keyboard input two data, return two number of large values
• B: Case Demo
  • Requirements: Keyboard input Two data, compare two number is equal

04.23_java Language Basics (method's output star and its invocation)

• A: Case Demo
  • Requirements: Based on the number of rows and columns entered by the keyboard, the output star in the console
• B: Method Invocation: (no return value, void)
  • called separately
  • Output Call (Error)
  • Assignment Invocation (Error)

04.24_java Language Basics (practice of methods)

• A: Case Demo
  • Requirements: Data output According to the keyboard input the corresponding multiplication table

04.25_java Language Basics (Method overloading overview and basic usage)

• A: Overview of method overloading
  • Summation case
    • 2 integers
    • 3 integers
    • 4 integers

• B: Method Overloading:

  • In the same class, the method name is the same, and the parameter list is different. Is independent of the return value type.

  • The parameter list is different:

    • A: Different number of parameters
    • B: Different parameter types
    • C: The order of the parameters is different (overloaded, but not in development)

04.26_java Language Basics (method overloading exercises compare data for equality)

• A: Case Demo
  • Requirement: Compare two data for equality.
  • parameter types are two int type, two double type, and are tested in the Main method

4th Loop Structure Overview and the format of the for statement and its use