added gaussian elimination method

Added Gaussian Elimination method. Thats write in cpp

Computer Oriented Statistical Methods/Gaussian_elimination.cpp

@@ -0,0 +1,59 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+    int mat_size,i,j,step;
+
+    cout<<"Matrix size: ";
+    cin>>mat_size;
+
+    double mat[mat_size+1][mat_size+1], x[mat_size][mat_size+1];
+
+    cout<<endl<<"Enter value of the matrix: "<<endl;
+    for(i=0;i<mat_size;i++)
+    {
+        for(j=0;j<=mat_size;j++)
+        {
+            cin>>mat[i][j];   //Enter (mat_size*mat_size) value of the matrix.
+        }
+    }
+
+    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]);
+        }
+    }
+
+    cout<<endl<<"Matrix using Gaussian Elimination method: "<<endl;
+    for(i=0;i<mat_size;i++)
+    {
+        for(j=0;j<=mat_size;j++)
+        {
+            x[i][j] = mat[i][j];
+            cout<<mat[i][j]<<" ";
+        }
+        cout<<endl;
+    }
+    cout<<endl<<"Value of the Gaussian Elimination method: "<<endl;
+    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]);
+
+        cout<<"x"<<i<<"= "<<x[i][i]<<endl;
+    }
+return 0;
+}