Change project structure to a Maven Java project + Refactor (#2816)

src/main/java/com/thealgorithms/maths/Gaussian.java

@@ -0,0 +1,71 @@
+/**
+ * \file
+ * \brief [Gaussian elimination
+ * method](https://en.wikipedia.org/wiki/Gaussian_elimination)
+ */
+package com.thealgorithms.maths;
+
+import java.util.*;
+
+/**
+ * Main function
+ */
+public class Gaussian {
+
+    public static void main(String[] args) {
+        int mat_size, i, j, step;
+        Scanner sc = new Scanner(System.in);
+
+        System.out.println("Matrix Size : ");
+        mat_size = sc.nextInt();
+
+        double[][] mat = new double[mat_size + 1][mat_size + 1];
+        double[][] x = new double[mat_size][mat_size + 1];
+
+        System.out.println("Enter value of the matrix");
+        System.out.println(' ');
+        for (i = 0; i < mat_size; i++) {
+            for (j = 0; j <= mat_size; j++) {
+                mat[i][j] = sc.nextInt();
+            }
+        }
+
+        // perform Gaussian elimination
+        for (step = 0; step < mat_size - 1; step++) {
+            for (i = step; i < mat_size - 1; i++) {
+                double a = (mat[i + 1][step] / mat[step][step]);
+
+                for (j = step; j <= mat_size; j++) {
+                    mat[i + 1][j] = mat[i + 1][j] - (a * mat[step][j]);
+                }
+            }
+        }
+
+        System.out.println("Matrix using Gaussian Elimination method: ");
+        System.out.println(" ");
+        for (i = 0; i < mat_size; i++) {
+            for (j = 0; j <= mat_size; j++) {
+                x[i][j] = mat[i][j];
+                System.out.print(mat[i][j] + " ");
+            }
+            System.out.println();
+        }
+        System.out.println("Value of the Gaussian Elimination method: ");
+        System.out.println(" ");
+
+        for (i = mat_size - 1; i >= 0; i--) {
+            double sum = 0;
+            for (j = mat_size - 1; j > i; j--) {
+                x[i][j] = x[j][j] * x[i][j];
+                sum = x[i][j] + sum;
+            }
+            if (x[i][i] == 0) {
+                x[i][i] = 0;
+            } else {
+                x[i][i] = (x[i][mat_size] - sum) / (x[i][i]);
+            }
+            System.out.print("x" + i + "=" + x[i][i]);
+            System.out.println(" ");
+        }
+    }
+}