Splitting/dividing vector

[yat89]

Hi everyone. I would like to ask. I got a task to split or divide vector and copy it into new vector. I don't have idea how to do it. Is there any ways to do it? Any advice greatly appreciated.

The situation is as follows:
In the following code, vector has been summed up and each time the amount of the summation reaches 15, zero will be inserted. But now, in the next task I need to split the vector each time the summation reaches 15. The new vector need to be creates from each vector row.

Original vector:
0 5 3 2 4 6 7 1 6 5 3 1 8 6 1 9 3 2 1
0 0 6 7 1 6 5 3 9 3 2 1 7 6 2 5 3 2 4
0 8 6 1 9 3 3 1 6 7 1 5 2 3 4 6 5 3 1

Here is the output I got after inserting zero:
0 5 3 2 4 0 6 7 1 0 6 5 3 1 0 8 6 1 0 9 3 2 1
0 0 6 7 1 0 6 5 3 0 9 3 2 1 0 7 6 2 0 5 3 2 4
0 8 6 1 0 9 3 3 0 1 6 7 1 0 5 2 3 4 0 6 5 3 1

Now, after split, the output should be as:

New vector for row 1:
0 5 3 2 4
0 6 7 1
0 6 5 3 1
0 8 6 1
0 9 3 2 1
New vector for row 2:
0 0 6 7 1
0 6 5 3
0 9 3 2 1
0 7 6 2
0 5 3 2 4
New vector for row 3:
0 8 6 1
0 9 3 3
0 1 6 7 1
0 5 2 3 4
0 6 5 3 1

Here is the code:

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

using namespace std;

const int row = 3;	 
const int col = 19;

vector<vector<int> > vec(row, vector <int>(col, 0));
vector<vector<int> > new_vec_row1(5, vector <int>(5, 0));
vector<vector<int> > new_vec_row2(5, vector <int>(5, 0));
vector<vector<int> > new_vec_row3(5, vector <int>(5, 0));

int main () 
{ 
    // Input file
	ifstream inpData("myData.txt");
	
	// Assign data into array 
	cout << "Original vector: "; 
		cout << endl;
	for (int i = 0; i < row; i++)
	{
		for (int j = 0; j < col; j++)
		{
			inpData >> vec[i][j];
			cout << "  " << vec[i][j];
		}
		cout << endl;
	}
	cout << endl;
	
	// Close input files
	inpData.close();

	for (int i = 0; i < row; i++)
	{
		int sum = 0;
		int Q = 15;
    
		// Iterator used to store the position of searched element 
		vector<int>::iterator itr; 
	
		for (itr = vec[i].begin(); itr != vec[i].end(); itr++)
		{
			if (sum + *itr > Q)
			{
				// inserting an element invalidates the iterator, get a new one
				itr = vec[i].insert(itr, 0);
				sum = 0;
			}
			sum += *itr;
		}
	}

	// Print new vector 
	cout << "New vector with inserting element: "; 
		cout << endl;
    for (int i = 0; i < vec.size(); i++) 
	{
		for (int j = 0; j < vec[i].size(); j++)
		{
			cout << "  " << vec[i][j];
		}
		cout << endl;
	}   
    cout << endl; 

	system("pause");
	return 0;
}

[nuderobmonkey]

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <sstream>

using namespace std;

const int row = 3;	 
const int col = 19;


vector<vector<int> > vec(row, vector <int>(col, 0));

// I've placed all target vectors themselve into a vector :)

//vector<vector<int> > new_vec_row1(5, vector <int>(5, 0));
//vector<vector<int> > new_vec_row2(5, vector <int>(5, 0));
//vector<vector<int> > new_vec_row3(5, vector <int>(5, 0));

using ull = unsigned long long;

// I've put the data of the file into a istringstream for
// making able testing the program at an online compiler :)
istringstream inpData(
"0 5 3 2 4 6 7 1 6 5 3 1 8 6 1 9 3 2 1 \
0 0 6 7 1 6 5 3 9 3 2 1 7 6 2 5 3 2 4 \
0 8 6 1 9 3 3 1 6 7 1 5 2 3 4 6 5 3 1"
);

int main () 
{ 
    // Input file
//	ifstream inpData("myData.txt");
	
	// Assign data into array 
	cout << "Original vector: "; 
		cout << endl;
	for (int i = 0; i < row; i++)
	{
		for (int j = 0; j < col; j++)
		{
			inpData >> vec[i][j];
			cout << "  " << vec[i][j];
		}
		cout << endl;
	}
	cout << endl;
	
	// Close input files
//	inpData.close();

	for (int i = 0; i < row; i++)
	{
		int sum = 0;
		int Q = 15;
    
		// Iterator used to store the position of searched element 
		vector<int>::iterator itr; 
	
		for (itr = vec[i].begin(); itr != vec[i].end(); itr++)
		{
			if (sum + *itr > Q)
			{
				// inserting an element invalidates the iterator, get a new one
				itr = vec[i].insert(itr, 0);
				sum = 0;
			}
			sum += *itr;
		}
	}

	// Print new vector 
	cout << "New vector with inserting element: "; 
		cout << endl;
    for (ull i = 0; i < vec.size(); i++) 
	{
		for (ull j = 0; j < vec[i].size(); j++)
		{
			cout << "  " << vec[i][j];
		}
		cout << endl;
	}   
    cout << endl; 


    // splitting the vectors
    vector<vector<vector<int>>> splitted_v;  // Holds all three overall vectors
    vector<vector<int>> splitted_row_v;   // Holds the vector of a row
    vector<int> splitted_num_v;          // Holds a sequence
    for (ull row = 0; row < vec.size(); row++)
    {   
        // Handling each row
        bool zero_at_begin = true;
        for (ull col = 0; col < vec[row].size(); col++)
        {
            // Handling preceding zeros specially
            int n = vec[row][col];
            if (n != 0) zero_at_begin = false;
            if (n == 0 && zero_at_begin)
            {
                splitted_num_v.push_back(n);
                continue;
            }
            if ( vec[row][col] == 0)
            {
                splitted_row_v.push_back(splitted_num_v);
                splitted_num_v.clear();
            }
            splitted_num_v.push_back( vec[row][col] );
        }
        splitted_row_v.push_back( splitted_num_v );
        splitted_num_v.clear();
        splitted_v.push_back( splitted_row_v);
        splitted_row_v.clear();
    }
    
    // Printing the splitted vectors:        
    for (ull i = 0; i < splitted_v.size(); i++)
    {
        std::cout << "New vector for row " << i+1 << ":\n";
        for (ull row = 0; row < splitted_v[i].size(); row++)
        {
            for (ull col = 0; col < splitted_v[i][row].size(); col++)
            {
                cout << "  " << splitted_v[i][row][col];
            }
            cout << endl;
        }
    }
    
        
	system("pause");
	return 0;
}

http://coliru.stacked-crooked.com/a/50a5f5fff775f1ba
Maybe there is a shorter solution possibele by using the std algorithm library facilities.

[keskiverto]

The vector has a constructor that accepts a range: http://www.cplusplus.com/reference/vector/vector/vector/

Given iterators foo and bar that are valid for vector gaz and bar==foo+n:

std::vector copy( foo, bar );
// use the copy 

Considering that you will append copies to a list:

vector<vector<int>> list;

list.emplace_back( foo, bar ); // append a copy 

[yat89]

Hi nuderobmonkey and keskiverto,

Thanks a lot for the help from both of you. I will try to learn from your code and will try to find out other possible solution using std algorithm.

Really appreciated.