added matrix multiplication in Array Questions

Array Questions/matrix_multiplication.c

@@ -0,0 +1,81 @@
+// matrix multiplication
+
+#include <stdio.h>
+#include <stdlib.h>
+int mult_matrix(int, int, int, int);
+
+int main(int argc, char *argv[]) {
+  int row1, column1, row2, column2;
+  printf("================================\n");
+  printf("Enter number of rows and columns for the first matrix:\n");
+  scanf("%d%d", &row1, &column1);
+  printf("================================\n");
+  printf("Enter number of rows and columns for  the second matrix:\n");
+  scanf("%d%d", &row2, &column2);
+  printf("================================\n");
+  // check to see if any of the rows and columns are negative
+  if (((row1 * column1) < 1) && ((row2 * column2) < 1)) {
+    printf("Enter non-negative value.\n");
+    exit(EXIT_FAILURE);
+  } else {
+    if (column1 != row2) {
+      // check to see if the number of rows of first matrix is equal to the
+      // number of columns of second matrix;
+      printf("Number of column of first matrix must be equal the row of second "
+             "matrix.\n");
+      exit(EXIT_FAILURE);
+
+    } else {
+      // if all the conditions are true, then call the mult_matrix function
+      mult_matrix(row1, column1, row2, column2);
+    }
+  }
+
+  return 0;
+}
+
+int mult_matrix(int row1, int column1, int row2, int column2) {
+  int arr1[row1][column1], arr2[row2][column2];
+  // take input for first matrix
+  for (int i = 0; i < row1; i++) {
+    for (int j = 0; j < column1; j++) {
+      printf("For first matrix:\n");
+      printf("Enter element number [%d][%d]:\n", i + 1, j + 1);
+      scanf("%d", &arr1[i][j]);
+    }
+  }
+
+  printf("================================\n");
+  // take input for second matrix
+  for (int i = 0; i < row2; i++) {
+    for (int j = 0; j < column2; j++) {
+      printf("For second matrix:\n");
+      printf("Enter element number [%d][%d]:\n", i + 1, j + 1);
+      scanf("%d", &arr2[i][j]);
+    }
+  }
+  printf("================================\n");
+
+  // multiplying the two matrixes
+  int result[row1][column2];
+  for (int i = 0; i < row1; i++) {
+    for (int j = 0; j < column2; j++) {
+      result[i][j] = 0;
+      for (int k = 0; k < column1; k++) {
+        // either column1 or row2 can be used
+        result[i][j] += arr1[i][k] * arr2[k][j];
+      }
+    }
+  }
+
+  // muliplied matrix
+  // printf("Result of the product of those two matrixes\n");
+  for (int i = 0; i < row1; i++) {
+    for (int j = 0; j < column2; j++) {
+      printf("%d\t", result[i][j]);
+    }
+    printf("\n");
+  }
+
+  return 0;
+}