To begin with, let’s create a simple custom object called Person with two properties: name and age.

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

Now, let’s assume that we have a vector of Person objects called people. We want to sort this vector based on the age property in ascending order. To achieve this, we can use the std::sort function from the C++ standard library.

std::vector<Person> people = {{"Alice", 25}, {"Bob", 30}, {"Charlie", 20}};

std::sort(people.begin(), people.end(), [](const Person& a, const Person& b) {
    return a.age < b.age;
});

In the code above, we pass a lambda function as the third argument to std::sort. This lambda function compares two Person objects based on their age property and returns true if the first object should come before the second object in the sorted sequence.

If we want to sort the vector in descending order, we can modify the lambda function to use the greater than (>) operator instead.

std::sort(people.begin(), people.end(), [](const Person& a, const Person& b) {
    return a.age > b.age;
});

In addition to sorting by a single property, we can also sort by multiple properties. For example, let’s sort the people vector first by age in ascending order, and then by name in descending order.

std::sort(people.begin(), people.end(), [](const Person& a, const Person& b) {
    if (a.age == b.age) {
        return a.name > b.name;
    }
    return a.age < b.age;
});

By adjusting the conditions in the lambda function, we can specify the custom sorting criteria based on the properties of the custom object.

In conclusion, sorting a vector of custom objects in C++ can be achieved by using the std::sort function along with a lambda function for custom comparison. By manipulating the conditions within the lambda function, we can define the sorting behavior based on the properties of the custom object.

#C++ #SortingVectors