Question

How to create a two dimensional (2D) vector in C++

Answer 1

#include <iostream>
#include <vector>

void Print2DVector(std::vector<std::vector<int>> vec2d) {
    for (std::vector<int> vec1d : vec2d) {
        for (int val : vec1d) {
            std::cout << val << " ";
        }    
        std::cout << "\n";
    }
}

int main(void) {
    std::vector<std::vector<int>> vec(3, std::vector<int>(4));
    
    Print2DVector(vec);
}
 
 
 
 
/*
run:
 
0 0 0 0 
0 0 0 0 
0 0 0 0 
 
*/

 

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Answer 2

#include <iostream>
#include <vector>
 
void Print2DVector(std::vector<std::vector<int>> vec2d) {
    for (std::vector<int> vec1d : vec2d) {
        for (int val : vec1d) {
            std::cout << val << " ";
        }    
        std::cout << "\n";
    }
}
 
int main(void) {
    int rows = 3, cols = 4;
    
    std::vector<std::vector<int>> vec(rows, std::vector<int>(cols, 0)); 
     
    Print2DVector(vec);
}
  
  
  
  
/*
run:
  
0 0 0 0 
0 0 0 0 
0 0 0 0 
  
*/

 

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