first cell sum up neighbours

2.matCent.cpp

// 2.matCent.cpp
// juanfc 2024-02-08
// https://gist.github.com/juanfal/a0ae972d1806eb00c3de0d4eef3cd76f

#include <iostream>
#include <array>
using namespace std;

const int R = 4;
const int C = 3;
typedef array<array<int,C>,R> TMat;


int main()
{
    void test(TMat m);

    test((TMat){{
        {{3,  1, 2}},
        {{2, 16, 2}},
        {{1,  3, 2}},
        {{5,  0, 6}}
    }});

    test((TMat){{
        {{2, 1, 7}},
        {{2, 5, 8}},
        {{2, 2, 1}},
        {{7, 7, 2}},
    }});

    test((TMat){{
        {{2, 1, 7}},
        {{2, 5, 8}},
        {{2, 2, 1}},
        {{7, 6, 9}},
    }});
    
    return 0;
}


void test(TMat m)
{
    void firstCent(TMat m, int& the_r, int& the_c);
    void printMat(TMat m);

    cout << "Matrix:" << endl;
    printMat(m);
    int the_r, the_c;
    firstCent(m, the_r, the_c);
    cout << "First cell satisfying the condition: ("
         << the_r << ", " << the_c << ")" << endl << endl;
}

void firstCent(TMat m, int& the_r, int& the_c)
{
    int sumNeigh(TMat m, int a_row, int a_col);

    int r = 0;
    the_r = the_c = -1;
    while (r < R and the_r == -1) {
        int c = 0;
        while (c < C and sumNeigh(m, r, c) != m[r][c])
            ++c;
        if (c < C) { // found
            the_r = r;
            the_c = c;
        } else
            ++r;
    }
}

int sumNeigh(TMat m, int a_row, int a_col)
{
    bool isIn(int i, int j);

    int s = 0;
    for (int i = -1; i <= 1; ++i)
        for (int j = -1; j <= 1; ++j)
            if ((i != 0 or j != 0)
                  and isIn(a_row+i, a_col+j) )
                s += m[a_row+i][a_col+j];
    return s;
}
void printMat(TMat m)
{
    for (int r = 0; r < R; ++r) {
        for (int c = 0; c < C; ++c)
            cout << m[r][c] << " ";
        cout << endl;
    }
}

bool isIn(int i, int j)
{
    return  i >= 0 and i < R and
            j >= 0 and j < C;
}

// 3 1 2
// 2 16 2
// 1 3 2
// 5 1 6
// First cell satisfying the condition: (1,1)

// Matrix:
// 2 1 7
// 2 5 8
// 2 2 1
// 7 7 2
// First cell satisfying the condition: (-1,-1)

// Matrix:
// 2 1 7
// 2 5 8
// 2 2 1
// 7 6 9
// First cell satisfying the condition: (3,2)