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Languages that support pointers are very convenient to implement variable exchange. Languages that do not support pointers are easier to implement with tuple or array destructuring. However, Java does not seem to be able to exchange the values of two variables directly with functions, unless they are wrapped with objects or arrays.
The following are sample codes for exchanging two variable values with functions using Java, JavaScript, Go, C, C++, and Python respectively, and provide a brief description:
Java
public class Main { public static void main(String[] args) { int a = 5; int b = 10; System.out.println("Before swap: a = " + a + ", b = " + b); swap(a, b); System.out.println("After swap: a = " + a + ", b = " + b); } public static void swap(int x, int y) { int temp = x; x = y; y = temp; } }
In Java, parameters are passed by value, so what is exchanged in swap function is the temporary variable in the function, without affecting the variables in main function.
JavaScript
function swap(a, b) { [a, b] = [b, a]; return [a, b]; } let x = 5; let y = 10; console.log(`Before swap: x = ${x}, y = ${y}`); [x, y] = swap(x, y); console.log(`After swap: x = ${x}, y = ${y}`);
In JavaScript, the values of two variables can be easily swapped using the destructuring assignment syntax.
Go
package main import "fmt" func main() { a := 5 b := 10 fmt.Printf("Before swap: a = %d, b = %d\n", a, b) swap(&a, &b) fmt.Printf("After swap: a = %d, b = %d\n", a, b) } func swap(x, y *int) { temp := *x *x = *y *y = temp }
In Go, variables outside functions can be modified by passing pointers.
C
#include <stdio.h> void swap(int *x, int *y) { int temp = *x; *x = *y; *y = temp; } int main() { int a = 5; int b = 10; printf("Before swap: a = %d, b = %d\n", a, b); swap(&a, &b); printf("After swap: a = %d, b = %d\n", a, b); return 0; }
In C language, variables outside functions can be modified by passing pointers.
C++
#include <iostream> void swap(int &x, int &y) { int temp = x; x = y; y = temp; } int main() { int a = 5; int b = 10; std::cout << "Before swap: a = " << a << ", b = " << b << std::endl; swap(a, b); std::cout << "After swap: a = " << a << ", b = " << b << std::endl; return 0; }
In C++, you can use references to modify variables outside functions.
Python
def swap(a, b): return b, ax = 5 y = 10 print(f"Before swap: x = {x}, y = {y}") x, y = swap(x, y) print(f"After swap: x = {x}, y = {y}")
In Python, you can use tuple unpacking to swap the values of two variables.
These sample codes demonstrate how to use functions to swap the values of two variables and provide brief instructions. Note that different programming languages may differ in variable passing and syntax.
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