Initial commit

lab_2/main.java

@@ -0,0 +1,109 @@
+package lab_2;
+
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Scanner;
+
+public class main {
+
+    public static short protectedInput(String inputPrompt, String errorMessage, Scanner input) {
+        short read_variable;
+
+        do {
+            try {
+                System.out.println();
+                System.out.print(inputPrompt);
+
+                read_variable = input.nextShort();
+                break;
+            } catch (Exception e) {
+                System.out.println(errorMessage);
+                input.nextLine();
+            }
+        } while (true);
+
+        return read_variable;
+    }
+
+    @NotNull
+    public static String format(int number) {
+        int width = String.valueOf(number).length() + 1;
+
+        return "|%" + width + "d ";
+    }
+
+    @Contract(pure = true)
+    public static double average(@NotNull short[] row) {
+        short sum = 0;
+
+        for (short element : row) {
+            sum += element;
+        }
+
+        return (double) sum / row.length;
+    }
+
+    public static void main(String[] args) {
+        short rows, columns;
+
+        Scanner input = new Scanner(System.in);
+
+        final short a = protectedInput("Input a constant to multiply a matrix by: ",
+                "A constant must be a short-data type integer, try again.", input);
+
+        System.out.println();
+        System.out.println("Input size of the matrix.");
+
+        do {
+            rows = protectedInput("Rows: ",
+                    "A number of rows must be a short-data type integer, try again.", input);
+        } while (rows <= 0);
+
+        do {
+            columns = protectedInput("Columns: ",
+                    "A number of columns must be a short-data type integer, try again.", input);
+        } while (columns <= 0);
+
+        input.close();
+
+        short[][] matrix_B = new short[rows][columns];
+
+        System.out.println();
+        System.out.println("Matrix B:");
+
+        String format = format(rows * columns);
+
+        for (short i = 0; i < rows; i++) {
+            for (short j = 0; j < columns; j++) {
+                matrix_B[i][j] = (short) ((i + 1) * (j + 1));
+
+                System.out.printf(format, matrix_B[i][j]);
+            }
+
+            System.out.println("|");
+        }
+
+        System.out.println();
+        System.out.println("Matrix a×B:");
+
+        format = format(rows * columns * a);
+
+        for (short i = 0; i < matrix_B.length; i++) {
+            for (short j = 0; j < matrix_B[i].length; j++) {
+                matrix_B[i][j] *= (a);
+
+                System.out.printf(format, matrix_B[i][j]);
+            }
+
+            System.out.println("|");
+        }
+
+        System.out.println();
+        System.out.println("Averages of each row:");
+
+        for (short[] row : matrix_B) {
+            System.out.println(average(row));
+        }
+    }
+}