How are objects passed and returned as parameters in C++? (code example)

In C, we can pass objects of a class as parameters and return them from functions just like passing and returning other variables; no special keywords or header files are required. The following article will take you through it, I hope it will be helpful to you.

1. Pass the object as a parameter

To pass the object as a parameter, we pass the object The name is written as a parameter and the function is called in the same way as for other variables.

Basic syntax:

函数名(对象名);

Example:

#include <bits/stdc++.h> 
using namespace std; 
  
class Example { 
public: 
    int a; 
  
    // 此函数将对象作为参数
    void add(Example E) 
    { 
        a = a + E.a; 
    } 
}; 
int main() 
{ 
  
    // 创建对象
    Example E1, E2; 
  
    // 两个对象的值都已初始化
    E1.a = 50; 
    E2.a = 100; 
  
    cout << "初始值 \n"; 
    cout << "对象1的值： " << E1.a 
         << "\n对象2的值： " << E2.a 
         << "\n\n"; 
  
    // 将对象作为参数传递给函数add()
    E2.add(E1); 
  
    // 传递给函数add()后
    cout << "新值 \n"; 
    cout << "对象1的值： " << E1.a 
         << "\n对象2的值：" << E2.a 
         << "\n\n"; 
  
    return 0; 
}

Output:

初始值
对象1的值：50
对象2的值：100


新值
对象1的值：50
对象2的值：150

Explanation: In this example, there is a class with an integer variable " a" and a function "add" that takes an object as a parameter. The add() function is called with an object and another object as a parameter. Inside the function, the integer value of the parameter object is added to the integer value of the calling 'add' function. In this method, we can pass objects as parameters and change them;

Note: The add function does not return any value because its return type is void.

2. Return the object as a parameter

Basic syntax:

object = return object_name;

Example: the add function returns the "example" type The object (i.e. class name) whose value is stored in E3.

#include <bits/stdc++.h> 
using namespace std; 
  
class Example { 
public: 
    int a; 
  
    // 此函数将以对象为参数并返回对象
    Example add(Example Ea, Example Eb) 
    { 
        Example Ec; 
        Ec.a = Ec.a + Ea.a + Eb.a; 
  
        // 返回对象
        return Ec; 
    } 
}; 
int main() 
{ 
    Example E1, E2, E3; 
  
    // 两个对象的值都已初始化
    E1.a = 50; 
    E2.a = 100; 
    E3.a = 0; 
  
    cout << "初始值 \n"; 
    cout << "对象1的值: " << E1.a 
         << " \n对象2的值: " << E2.a 
         << "\n对象3的值: " << E3.a 
         << "\n\n"; 
  
    //将对象作为参数传递给函数add（）。
    E3 = E3.add(E1, E2); 
  
    // 将对象作为参数传递后更改的值
    cout << "新值 \n"; 
    cout << "对象1的值: " << E1.a 
         << " \n对象2的值: " << E2.a 
         << " \n对象3的值: " << E3.a 
         << "\n"; 
  
    return 0; 
}

Output:

初始值
对象1的值：50
对象2的值：100
对象3的值：0


新值
对象1的值：50
对象2的值：100
对象3的值：200

Description: In this example, we can see two aspects, how we pass objects and return them. When the object E3 calls the add function, it passes two other objects, E1 and E2, as parameters. Inside the function, another object is declared that calculates the sum of all three variables and returns it to E3.

Recommended related video tutorials: "C Tutorial"

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