Summary  
Passing structs by reference to functions lets you modify the original struct’s data directly from within the function.

General domain of usage  
Data manipulation in applications

When you pass a struct **by reference** to a function, any changes made inside the function affect the **original struct**, allowing you to **modify its data directly**. This is especially useful for updating specific fields, such as changing the **`age`** of a `Person` struct.


#define CATCH_CONFIG_MAIN
#include <catch2/catch.hpp>

struct Person {
    std::string name;
    int age;
};

void updateAge(Person& p, int newAge);

TEST_CASE("updateAge updates the age to 35", "[updateAge]") {
    Person alice{"Alice", 30};
    updateAge(alice, 35);
    REQUIRE(alice.age == 35);
}

TEST_CASE("updateAge updates the age to 0", "[updateAge]") {
    Person bob{"Bob", 25};
    updateAge(bob, 0);
    REQUIRE(bob.age == 0);
}

TEST_CASE("updateAge handles negative age", "[updateAge]") {
    Person charlie{"Charlie", 40};
    updateAge(charlie, -5);
    REQUIRE(charlie.age == -5);
}

test.cpp

Master the essentials of C++ structures and enumerations. Learn how to define, use, and combine structs and enums to model real-world data, and practice with hands-on coding tasks.

Explore the basics of structs in C++, including their syntax, initialization, and how they differ from classes.

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Discover how enums provide named constants and how to use them effectively.

Challenge: Passing Structs to Functions

Solution

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Challenge: Passing Structs to Functions

Solution