How to check if a Vector contains all the items of Another Vector in C++ - Step by Step Examples

How to check if a Vector contains all the items of Another Vector in C++ ?

Answer

To check if a vector contains all the items of another vector in C++, you can use the std::all_of algorithm combined with the std::find algorithm.

✐ Examples

1 Check if All Elements of One Vector are in Another Vector

In this example,

We include the necessary headers: #include <vector>, #include <algorithm>, and #include <iostream> for working with vectors, algorithms, and input/output streams.
We create a vector named vec1 with a set of numerical values.
We create another vector named vec2 with a different set of numerical values.
We use the std::all_of algorithm to check if all elements of vec2 are present in vec1. The std::all_of algorithm takes a range and a predicate. The range is defined by vec2.begin() and vec2.end(), and the predicate is a lambda function that checks if each element of vec2 is found in vec1 using the std::find algorithm.
The std::find algorithm searches for an element in vec1 and returns an iterator to the found element or vec1.end() if the element is not found.
The std::all_of algorithm returns true if the predicate is true for all elements in the range; otherwise, it returns false.
Finally, we print the result to standard output using std::cout.

C++ Program

#include <vector>
#include <algorithm>
#include <iostream>

int main() {
    std::vector<int> vec1 = {1, 2, 3, 4, 5};
    std::vector<int> vec2 = {2, 3, 4};
    bool result = std::all_of(vec2.begin(), vec2.end(), [&vec1](int item) {
        return std::find(vec1.begin(), vec1.end(), item) != vec1.end();
    });
    std::cout << std::boolalpha << result << std::endl;
    return 0;
}

Output

true

2 Check if All Elements of Another Vector are in the First Vector

In this example,

We include the necessary headers: #include <vector>, #include <algorithm>, and #include <iostream> for working with vectors, algorithms, and input/output streams.
We create a vector named main_vec with a series of character strings.
We create another vector named sub_vec with a subset of character strings.
We use the std::all_of algorithm to check if all elements of sub_vec are present in main_vec. The std::all_of algorithm takes a range and a predicate. The range is defined by sub_vec.begin() and sub_vec.end(), and the predicate is a lambda function that checks if each element of sub_vec is found in main_vec using the std::find algorithm.
The std::find algorithm searches for an element in main_vec and returns an iterator to the found element or main_vec.end() if the element is not found.
The std::all_of algorithm returns true if the predicate is true for all elements in the range; otherwise, it returns false.
Finally, we print the result to standard output using std::cout.

C++ Program

#include <vector>
#include <algorithm>
#include <iostream>

int main() {
    std::vector<std::string> main_vec = {"apple", "banana", "cherry", "date", "fig"};
    std::vector<std::string> sub_vec = {"banana", "cherry", "date"};
    bool result = std::all_of(sub_vec.begin(), sub_vec.end(), [&main_vec](const std::string& item) {
        return std::find(main_vec.begin(), main_vec.end(), item) != main_vec.end();
    });
    std::cout << std::boolalpha << result << std::endl;
    return 0;
}

Output

true

3 Check if All Elements of a Subset Vector are in the Main Vector

In this example,

We include the necessary headers: #include <vector>, #include <algorithm>, and #include <iostream> for working with vectors, algorithms, and input/output streams.
We create a vector named primary_vec with a list of mixed data types including numbers and strings.
We create another vector named secondary_vec with some elements that are not present in primary_vec.
We use the std::all_of algorithm to check if all elements of secondary_vec are present in primary_vec. The std::all_of algorithm takes a range and a predicate. The range is defined by secondary_vec.begin() and secondary_vec.end(), and the predicate is a lambda function that checks if each element of secondary_vec is found in primary_vec using the std::find algorithm.
The std::find algorithm searches for an element in primary_vec and returns an iterator to the found element or primary_vec.end() if the element is not found.
Since not all elements of secondary_vec are in primary_vec, the std::all_of algorithm returns false.
Finally, we print the result to standard output using std::cout.

C++ Program

#include <vector>
#include <algorithm>
#include <iostream>

int main() {
    std::vector<std::variant<int, std::string>> primary_vec = {10, 20, 30, "apple", "banana"};
    std::vector<std::variant<int, std::string>> secondary_vec = {20, "banana", "cherry"};
    bool result = std::all_of(secondary_vec.begin(), secondary_vec.end(), [&primary_vec](const auto& item) {
        return std::find(primary_vec.begin(), primary_vec.end(), item) != primary_vec.end();
    });
    std::cout << std::boolalpha << result << std::endl;
    return 0;
}

Output

false

Summary

In this tutorial, we learned How to check if a Vector contains all the items of Another Vector in C++ language with well detailed examples.

◀ Previous Next ▶

C++ Tutorials

C++ How-Tos

How to check if a Vector contains all the items of Another Vector in C++ - Step by Step Examples

How to check if a Vector contains all the items of Another Vector in C++ ?

Answer

✐ Examples

1 Check if All Elements of One Vector are in Another Vector

C++ Program

Output

2 Check if All Elements of Another Vector are in the First Vector

C++ Program

Output

3 Check if All Elements of a Subset Vector are in the Main Vector

C++ Program

Output

Summary

More C++ Vectors Tutorials