Question

How to use for_each_n to modify part of vector elements in C++

Answer 1

#include <algorithm>
#include <iostream>
#include <vector>
 
void printVector(std::vector<int> const &vec) {
    for (auto const &n: vec) {
        std::cout << n << " ";
    }
}
 
int main()
{
    std::vector<int> vec {1, 2, 3, 4, 5};

    std::for_each_n(vec.begin(), 3, [](auto& n) { n *= 3; });
    
    printVector(vec);
}



  
/*
run:
  
3 6 9 4 5 
  
*/

 

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