Question

How to check if a vector contains a value in C++

Answer 1

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

int main()
{
    std::vector<int> v = { 5, 7, 1, 0, 9, 3, 8 };
    int val = 3;
 
    if (std::count(v.begin(), v.end(), val)) {
        std::cout << "found";
    }
    else {
        std::cout << "Not found";
    }
}




/*
run:

found

*/

 

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Answer 2

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

int main()
{
    std::vector<int> v = { 5, 7, 1, 0, 9, 3, 8 };
    int val = 3;
 
    if (std::find(v.begin(), v.end(), val) != v.end()) {
        std::cout << "found";
    }
    else {
        std::cout << "Not found";
    }
}




/*
run:

found

*/

 

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Answer 3

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

bool Contains(const std::vector<int> &v, int x) {
    return std::find(v.begin(), v.end(), x) != v.end();
}

int main() {
    std::vector<int> v = {5, 7, 1, 0, 9, 3, 8};
    int val = 9;

    std::cout << (Contains(v, val) ? "yes": "no");
}




/*
run:

yes

*/

 

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