How to define and call methods with parameters and return values in Java

Definition and call of methods with parameters

Formal parameters and actual parameters

Formal parameters: parameters in method definition

Equivalent to the variable definition format, for example int number

Actual parameters: Parameters in method calls

are equivalent to variables or constants, such as 10, number

Method exercises with parameters

Requirements: Design a method Used to print the maximum number of two numbers, the data comes from the method parameters

Idea:

1. Define a method to print the maximum number of two books, such as getMax()

public static void getMax( ){ }

2. Define two parameters for the method to receive data

public static void getMax(int a,int b){ }

3. Use branch statements to process the size relationship of numbers in two situations;

if (a>b){ system.out.println(a); }else{ system.out.printf(b);

4. Call the defined method in the main method (using constants)

public static void main（String[ ] args）{ //直接传递常量 getMax（10,20）； }

5. Call the defined method in the main method (using variables)

public static void main（String[ ] args）{ //定义变量，传递 int a=10； int b=20； getMax（a,b）; }

Code example:

public static void main(String[] args) { // TODO Auto-generated method stub getMax(10, 20);//使用常量 int a=10; int b=20; getMax(a, b);//使用变量 } public static void getMax(int a,int b){ if (a>b){ System.out.println(a); }else{ System.out.println(b); } }

Definition and call of methods with return values

Definition of methods with return values

Format:

public static data type Method name ( Parameters) {

return data;

# return true;

return 100; #Method call with return value

Method name (parameter);

Example:

isEvenNumber(5);

Data type Variable name = Method name (parameter);

Example:

boolean Number = isEvennumber(5);

Sample code: Define a method that receives a parameter, determines whether the data is an even number, and returns true or false

public static void main(String[] args) { //数据类型 变量名 = 方法名(参数) boolean flag= isEvenNumber(10); System.out.println(flag); } public static boolean isEvenNumber(int number) { if(number%2==0){ return true; }else{ return false; } }

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