When working with a 2D vector in programming, you may come across a situation where you need to count the occurrences of a specific element. In this blog post, we will explore how to accomplish this task using C++.

Approach

We will iterate through each row of the 2D vector and then through each element in that row to check if it matches the target element. If a match is found, we will increment a counter variable.

Example Code

Let’s take a look at the following example code that demonstrates how to count the occurrences of an element in a 2D vector in C++:

#include <iostream>
#include <vector>

// Function to count occurrences of an element in a 2D vector
int countOccurrences(const std::vector<std::vector<int>>& vec, int target) {
    int count = 0;
    for (const auto& row : vec) {
        for (const auto& element : row) {
            if (element == target) {
                count++;
            }
        }
    }
    return count;
}

int main() {
    std::vector<std::vector<int>> vec = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };

    int target = 5;

    int occurrences = countOccurrences(vec, target);

    std::cout << "The element " << target << " occurs " << occurrences << " times." << std::endl;

    return 0;
}

In this code, we define a function countOccurrences that takes a 2D vector vec and a target element target as parameters. It initializes a counter count with a value of 0. We then use nested for-loops to iterate through each element in the 2D vector. If the current element matches the target element, we increment the count variable.

In the main function, we define a sample 2D vector vec and a target element target (in this case, 5). We then call the countOccurrences function to get the number of occurrences of the target element and print the result.

Conclusion

Counting the occurrences of an element in a 2D vector can be easily achieved by iterating through each element and comparing it to the target element. In this blog post, we provided an example code in C++ that demonstrates how to implement this functionality. This approach can be extended or modified to suit your specific requirements.

#programming #C++