How to check if Two Lists are Equal in C++ - Step by Step Examples

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How to check if Two Lists are Equal in C++ ?

Answer

To check if two lists are equal in C++ using std::list, you can iterate over both lists and compare each element.

✐ Examples

1 Check Equality for Equal Lists

In this example,

We create two lists: list1 and list2 with equal values.
We iterate over both lists simultaneously using iterators.
We compare each corresponding element of list1 and list2.
If all elements are equal, then the lists are considered equal.
Finally, we print the result to standard output.

C++ Program

#include <iostream>
#include <list>

int main() {
    std::list<int> list1 = {1, 2, 3};
    std::list<int> list2 = {1, 2, 3};
    bool equal = true;
    if (list1.size() != list2.size()) {
        equal = false;
    }
    else {
        auto it1 = list1.begin();
        auto it2 = list2.begin();
        while (it1 != list1.end()) {
            if (*it1 != *it2) {
                equal = false;
                break;
            }
            ++it1;
            ++it2;
        }
    }
    std::cout << std::boolalpha << "Are the lists equal? " << equal << std::endl;
    return 0;
}

Output

Are the lists equal? true

2 Check Equality for Unequal Lists

In this example,

We create two lists: list1 and list2 with different values.
We iterate over both lists simultaneously using iterators.
We compare each corresponding element of list1 and list2.
If any element is not equal, then the lists are considered unequal.
Finally, we print the result to standard output.

C++ Program

#include <iostream>
#include <list>

int main() {
    std::list<int> list1 = {1, 2, 3};
    std::list<int> list2 = {1, 2, 4};
    bool equal = true;
    if (list1.size() != list2.size()) {
        equal = false;
    }
    else {
        auto it1 = list1.begin();
        auto it2 = list2.begin();
        while (it1 != list1.end()) {
            if (*it1 != *it2) {
                equal = false;
                break;
            }
            ++it1;
            ++it2;
        }
    }
    std::cout << std::boolalpha << "Are the lists equal? " << equal << std::endl;
    return 0;
}

Output

Are the lists equal? false

Summary

In this tutorial, we learned How to check if Two Lists are Equal in C++ language with well detailed examples.

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How to check if Two Lists are Equal in C++ - Step by Step Examples

How to check if Two Lists are Equal in C++ ?

Answer

✐ Examples

1 Check Equality for Equal Lists

C++ Program

Output

2 Check Equality for Unequal Lists

C++ Program

Output

Summary

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