Three basic 2D matrix iteration problems

Matrix/2DMatrixFindRow.cpp

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+// CPP program to find the row
+// with maximum number of 1s
+#include <bits/stdc++.h>
+using namespace std;
+#define R 4
+#define C 4
+
+// Function that counts how many 1s there are in a row
+int count_ones(bool row[], int len) {
+    int count = 0;
+
+    for (int j = 0 ; j < len ; j++ ){
+        if(row[j] == 1){
+            count++;
+        }
+    }
+
+    return count;
+}
+
+// Function that returns index of row
+// with maximum number of 1s.
+int rowWithMax1s(int m, int n, bool mat[R][C]) {
+
+    int rowIndex = -1 ;
+    int maxCount = 0 ;
+
+    for(int i = 0 ; i < n ; i++){
+        int count = 0 ;
+
+        count = count_ones(mat[i], m);
+
+        if(count > maxCount){
+            maxCount = count ;
+            rowIndex = i ;
+        }
+    }
+
+    return rowIndex ;
+}
+
+
+// Driver Code
+int main()
+{
+    int m = 4;
+    int n = 4;
+
+    bool mat[R][C] = { {0, 0, 0, 1},
+                    {0, 1, 1, 1},
+                    {1, 1, 1, 1},
+                    {0, 0, 0, 0}};
+
+    cout << "Index of row with maximum 1s is " << rowWithMax1s(C, R, mat) << "\n";
+
+    return 0;
+}
+
+// This code is very basic, yet, it was authored by someone else, who posted it on geeksforgeeks,
+// and was edited slightly by myself to fit the educational purpose of this request.
+// Unknown author, https://www.geeksforgeeks.org/find-the-row-with-maximum-number-1s/

Matrix/2DMatrixSpiralForm.cpp

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+// C++ Program to print a matrix spirally
+
+#include <bits/stdc++.h>
+using namespace std;
+#define R 3
+#define C 6
+
+void print(int n) {
+    cout << n << " ";
+}
+
+void top_row(int n, int i, int l, int k, int a[R][C]) {
+    for (i = l; i < n; ++i) {
+        print(a[k][i]);
+    }
+}
+
+void right_column(int n, int m, int i, int k, int a[R][C]) {
+    for (i = k; i < m; ++i) {
+        print(a[i][n - 1]);
+    }
+}
+
+void bottom_row(int n, int m, int i, int l, int a[R][C]){
+    for (i = n - 1; i >= l; --i) {
+        print(a[m - 1][i]);
+    }
+}
+
+void left_column(int m, int i, int k, int l, int a[R][C]){
+    for (i = m - 1; i >= k; --i) {
+        print(a[i][l]);
+    }
+}
+
+void spiralPrint(int m, int n, int a[R][C])
+{
+    int i, k = 0, l = 0;
+
+    /* k - starting row index
+        m - ending row index
+        l - starting column index
+        n - ending column index
+        i - iterator
+    */
+
+    while (k < m && l < n) {
+        /* Print the first row from
+               the remaining rows */
+        top_row(n, i, l, k, a);
+        k++;
+
+        /* Print the last column
+         from the remaining columns */
+        right_column(n, m, i, k, a);
+        n--;
+
+        /* Print the last row from
+                the remaining rows */
+        if (k < m) {
+            bottom_row(n, m, i, l, a);
+            m--;
+        }
+
+        /* Print the first column from
+                   the remaining columns */
+        if (l < n) {
+            left_column(m, i, k, l, a);
+            l++;
+        }
+    }
+}
+
+/* Driver Code */
+int main()
+{
+    int a[R][C] = { { 1, 2, 3, 4, 5, 6 },
+                    { 7, 8, 9, 10, 11, 12 },
+                    { 13, 14, 15, 16, 17, 18 } };
+
+    // Function Call
+    spiralPrint(R, C, a);
+
+    cout << "\n";
+
+    return 0;
+}
+
+// This is code is a slightly edited version by rathbhupendra, edited to fit the educational purpose of this project.
+// The original codelet can be found in https://www.geeksforgeeks.org/print-a-given-matrix-in-spiral-form/

Matrix/2DMatrixSum.cpp

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+// C++ program for implementation of sum of the elements of a matrix
+
+#include <bits/stdc++.h>
+using namespace std;
+#define R 3
+#define C 4
+
+int sum_of_row(int row[], int len) {
+	int sum = 0;
+
+	for (int j = 0; j < len; j++){
+		sum += row[j];
+	}
+
+	return sum;
+}
+
+// A function to implement 2d matrix sum
+int MatrixSum2D(int n, int m, int matrix[R][C])
+{
+	int sum = 0;
+	for (int i = 0; i < n; i++){
+		sum += sum_of_row(matrix[i], m);
+	}
+	return sum;
+
+}
+
+// Driver code
+int main()
+{
+	int matrix[R][C] = {{0,1,0,0}, {0,3,0,0}, {2,0,0,4}};
+
+	cout << "Sum: \n";
+	cout << MatrixSum2D(R, C, matrix) << "\n";
+	return 0;
+}
+
+// This codelet should have all of the basics for a starter
+// to iterate through a matrix in a naive fashion