Flowchart Algorithm | Find Matrix in Cpp from Array - c++

Question

I have come across this exercise on the topic of Algorithms, using Flowchart to present and test the sum of the matrix rows separately.
The Exercise with Matric
0
1
-2
-2
2
5
1
3
-1
Until now, I don't know to calculate the matric with Flowchart, can you guys help me? It would be nice if you do that using Flowgorithm Application or any other similar app.
The results should be :
For the first row: -1
For the second: 5
For the third: 3
I did this, but I don't know how to optimize the code:
#include <iostream>
#include <vector>
using namespace std;
int main()
{
int rreshti[9] = {
0, 1, -2,
-2, 2, 5,
1, 3, -1,
};
int r1, r2, r3;
r1 = 0;
r2 = 0;
r3 = 0;
for(int i = 0; i <= 2; i++) {
r1 = r1 + rreshti[i];
};
cout << "Totali i reshtit te pare: " << r1 << endl;
for (int i = 3; i <= 5; i++) {
r2 = r2 + rreshti[i];
};
cout << "Totali i reshtit te pare: " << r2 << endl;
for (int i = 6; i <= 8; i++) {
r3 = r3 + rreshti[i];
};
cout << "Totali i reshtit te pare: " << r3 << endl;
return 0;
}

Answer 1

You can use nested loops as you would have used in a 2D matrix.
#include <iostream>
#include <vector>
using namespace std;
int main()
{
int no_of_rows = 3; // I would reccommend you to replace constants and use variables like this.
int no_of_cols = 3;
int rreshti[no_of_rows * no_of_cols] = {
0, 1, -2,
-2, 2, 5,
1, 3, -1,
};
vector<int> rowSum(no_of_rows, 0);
for(int i = 0; i < no_of_rows; i++){
for(int j = 0; j < no_of_cols; j++){
rowSum[i] += rreshti[i*no_of_cols + j];
}cout<<"Sum of row no. "<<(i+1)<<" is = "<<rowSum[i]<<endl;
}
return 0;
}