Myujth

I'm trying to print a bidimensional array in c++ but I have a problem. I followed the traditional way to print a vector vectorName.size() inside a for loop. So the way that I follow was this.

#include <stdio.h>
#include <iostream>
#include <vector>
#include <math.h>
#include <time.h>


using namespace std;

void impMat(vector < vector <int> >, vector < vector <int> >);

int main () 
 vector < vector <int> > A;
 vector < vector <int> > B;
 vector <int> temp;

 for(int j = 0; j < 4; j++)
 for(int i = 0; i < 5; i++)
 temp.push_back(i);
 
 A.push_back(temp);
 B.push_back(temp);
 

 impMat(A,B);
 cout << endl;
 return 0;


void impMat(vector < vector <int> > A,vector < vector <int> > B) 

 for(int i = 0; i < A.size(); i++)
 for(int j = 0; j < A[i].size(); j++)
 cout << A[i][j] << " ";
 
 cout << endl;
 
 cout << endl;
 for(int i = 0; i < B.size(); i++)
 for(int j = 0; j < B[i].size(); j++)
 cout << B[i][j] << " ";
 
 cout << endl;
 

But that's print something like this

0 1 2 3 4
0 1 2 3 4 0 1 2 3 4
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4

Expected output

0 1 2 3 4 
0 1 2 3 4
0 1 2 3 4
0 1 2 3 4

How do I could get to print correctly my vectors?

The problem basically is how you fill your vectors:

for(int j = 0; j < 4; j++)

 for(int i = 0; i < 5; i++)
 
 temp.push_back(i);
 
 A.push_back(temp);
 B.push_back(temp);
 // now temp yet contains all the values entered, so you produce:
 // 0, 1, 2, 3, 4 in first loop run,
 // 0, 1, 2, 3, 4 0, 1, 2, 3, 4 in second,
 // ...
 // most simple fix:
 temp.clear();

More efficient, though, as you want to have the same data anyway:

for(int i = 0; i < 5; i++)

 temp.push_back(i);


for(int i = 0; i < 4; i++)

 A.push_back(temp);
 B.push_back(temp);

Two simple ways of printg std::vectors of std::vectors:

#include <vector>
#include <iostream>

int main()

 std::vector<std::vector<int>> foo
 0, 1, 2, 3, 4 ,
 0, 1, 2, 3, 4 ,
 0, 1, 2, 3, 4 ,
 0, 1, 2, 3, 4 
 ;

 // range-based for-loops:
 for (auto const &row : foo) 
 for (auto const &col : row) 
 std::cout << col << ' ';
 
 std::cout.put('n');
 

 std::cout.put('n');

 // ordinary for-loops:
 for (std::size_t row; row < foo.size(); ++row) 
 for (std::size_t col; col < foo[row].size(); ++col) 
 std::cout << foo[row][col] << ' ';
 
 std::cout.put('n');