The swap function in Java (reproduced)

First, let's review the swap function design in C language

Pass-by-value: Can't fundamentally exchange two numbers

#include <stdio.h>

void swap(int a, int b) {

int temp;

temp = a; a = b; b = temp;

}

 

Bibliography: In C language, the address should be called

#include <stdio.h>

void swap(int &a, int &b) {

int temp;

temp = a; a = b; b = temp;

}

 

That's the problem. There is no pointer in Java, and there is no reference to ordinary variables. How do we pass references to ordinary types of variables?

Method 1: Use array

public static void swap(int[] data, int a, int b) {

int temp;

temp = data[a]; data[a] = data[b]; data[b] = temp;

}

 

Method two (misleading): Pass the reference through the packaging class Integer in java, the result: failure, because the packaging class in java does not allow to change the data field, personally understand: java will not provide the packaging class Integer data address, that is, reference, But provide surface data

Method 3: Define your own packaging class MyInteger

static class MyInteger { 
private int x; 
public MyInteger(int x) {
this.x = x; 
} 
public int getValue(){ 
return x; 
} 
public void changeValue(int x) { 
this.x = x; 
}
}

public static void swap(MyInteger a, MyInteger b) {
int t = a.getValue(); 
a.changeValue(b.getValue()); 
b.changeValue(t); 
}

 

Method 4: External inline, use this class directly

public class Sort {
 int a, b;
 public Sort(int a, int b) {
     this.a = a;
     this.b = b;
 }
 public void swap() {
     int temp;
     temp = a; a = b; b = temp;
 }
}

 

Above, personal reference
: https://blog.csdn.net/dadoneo/article/details/6577976