Merge pull request #199 from aniket-41/patch-1

2Stacks in an array

Author: heyimShivam

2StackInAnArray.cpp

@@ -0,0 +1,182 @@
+#include <iostream>
+#include <stdlib.h>
+
+using namespace std;
+
+class twoStacks
+{
+    int *arr;
+    int size;
+    int top1, top2;
+
+public:
+    twoStacks(int n)
+    {
+        size = n;
+        arr = new int[n];
+        top1 = -1;
+        top2 = size;
+    }
+
+    void push1(int x)
+    {
+        if (top1 < top2 - 1)
+        {
+            top1++;
+            arr[top1] = x;
+        }
+        else
+        {
+            cout << "Stack Overflow";
+            exit(1);
+        }
+    }
+
+    void push2(int x)
+    {
+
+        if (top1 < top2 - 1)
+        {
+            top2--;
+            arr[top2] = x;
+        }
+        else
+        {
+            cout << "Stack Overflow";
+            exit(1);
+        }
+    }
+
+    int pop1()
+    {
+        if (top1 >= 0)
+        {
+            int x = arr[top1];
+            top1--;
+            return x;
+        }
+        else
+        {
+            cout << "Stack UnderFlow";
+            return -1;
+        }
+    }
+
+    int pop2()
+    {
+        if (top2 < size)
+        {
+            int x = arr[top2];
+            top2++;
+            return x;
+        }
+        else
+        {
+            cout <<endl<< "Stack UnderFlow";
+            return -1;
+        }
+    }
+    void display()
+    {
+        cout << "Stack 1 ";
+        if (top1 >= 0)
+        {
+            for (int i = top1; i >= 0; i--)
+                cout << arr[i] << " ";
+        }
+        else
+            cout << "Stack is empty";
+
+    cout << endl;
+    cout << "Stack 2: " ;
+    if (top2 != size)
+    {
+        for (int i = top2; i < size; i++)
+        {
+            cout << arr[i] << " ";
+        }
+    }
+    else
+    {
+        cout << "Stack is empty";
+    }
+    cout << endl;
+    }
+};
+
+int main()
+{
+    int n;
+    cout << "Enter the size of the stack ";
+    cin >> n;
+
+    twoStacks ts(n);
+    int ch, val;
+
+    do
+    {
+        cout << "1) Push in stack 1" << endl;
+        cout << "2) Push in stack 2" << endl;
+        cout << "3) Pop from stack 1" << endl;
+        cout << "4) Pop from stack 2" << endl;
+        cout << "5) Display Stack" << endl;
+        cout << "6) Exit" << endl;
+        cout << "Enter choice: " << endl;
+        cin >> ch;
+        switch (ch)
+        {
+        case 1:
+        {
+            cout << "Enter value to be pushed in stack 1:" << endl;
+            cin >> val;
+            ts.push1(val);
+            break;
+        }
+        case 2:
+        {
+            cout << "Enter value to be pushed in stack 2: " << endl;
+            cin >> val;
+            ts.push2(val);
+            break;
+        }
+        case 3:
+        {
+
+            int x = ts.pop1();
+            if (x != -1)
+            {
+                cout << "Popped Value from stack 1 is " << x << endl;
+                break;
+            }
+            break;
+        }
+        case 4:
+        {
+
+            int x = ts.pop2();
+            if (x != -1)
+            {
+                cout << "Popped Value from stack 2 is " << x << endl;
+                break;
+            }
+            break;
+        }
+
+        case 5:
+        {
+            ts.display();
+            break;
+        }
+        case 6:
+        {
+            cout << "Exit" << endl;
+            break;
+        }
+        default:
+        {
+            cout << "Invalid Choice" << endl;
+        }
+        }
+
+    } while (ch != 6);
+}