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1]. DSA/1]. Data Structures/09]. Stack/C++/_05)_basics_of_array_imple_of_stack.cpp

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+#include <iostream>
+#include <math.h>
+#include <algorithm>
+#include <vector>
+#include <string>
+#include <string.h>
+#include <ctype.h>
+
+using namespace std;
+
+class stack{
+    int* arr;
+    int top;
+
+    public:
+    stack(int n)
+        {
+            arr = new int[n];
+            top= -1;
+        }
+
+    void push(int x,int n)
+        {
+            if(top == n-1)
+                {
+                    cout<<"\nStack Overflow";
+                    return;
+                }
+
+            top++;
+            arr[top] = x;
+        }
+
+    void pop()
+        {
+            if(top == -1)
+                {
+                    return;
+                }
+            top--;
+        }
+
+    int peek()
+        {
+            if(top == -1)
+                {
+                    cout<<"\nNo element ";
+                    return -1;
+                }
+            return arr[top];
+        }
+
+    bool empty()
+        {
+            return top==-1;
+        }
+};
+
+
+
+int main()
+    {
+        int n,x;
+        cin>>n;
+        stack st(n);
+
+
+        for(int i=0;i<n;i++)
+            {
+                cin>>x;
+                st.push(x,n);
+            }
+
+        for(int i=n;i>=0;i--)
+            {
+                cout<<st.peek()<<" ";
+                st.pop();
+            }
+
+        return 0; 
+    }

1]. DSA/1]. Data Structures/09]. Stack/C++/_06)_reverse_sentence_using_stack.cpp

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+#include <iostream>
+#include <math.h>
+#include <algorithm>
+#include <vector>
+#include <string>
+#include <string.h>
+#include <stack>
+#include <ctype.h>
+
+using namespace std;
+
+void reversestring(string s)
+    {
+        stack<string> st;
+
+        for(int i=0;i<s.length();i++)
+            {
+                string word="";
+                while(s[i]!=' ' && i<s.length())
+                    {
+                        word += s[i];
+                        i++;
+                    }
+                st.push(word);
+            }
+
+        while(!st.empty())
+            {
+                cout<<st.top()<<" ";
+                st.pop();
+            }
+        cout<<endl;
+    }
+
+int main()
+    {
+        string s;
+        cin.ignore();
+        getline(cin,s);
+        reversestring(s);
+
+        return 0; 
+    }

1]. DSA/1]. Data Structures/09]. Stack/C++/_07)_reverse_stack.cpp

@@ -0,0 +1,59 @@
+#include <iostream>
+#include <math.h>
+#include <algorithm>
+#include <vector>
+#include <string>
+#include <string.h>
+#include <stack>
+#include <ctype.h>
+
+using namespace std;
+
+void insertatbottom (stack<int> &st, int ele)
+    {
+        if(st.empty())
+            {
+                st.push(ele);
+                return;
+            }
+        int topele = st.top();
+        st.pop();
+        insertatbottom(st,ele);
+
+        st.push(topele);
+    }
+
+void reversestack(stack<int> &st)
+    {
+        if(st.empty())
+            {
+                return;
+            }
+
+        int ele = st.top();
+        st.pop();
+        reversestack(st);
+        insertatbottom(st,ele);
+    }
+
+int main()
+    {
+        stack<int> st;
+        int n,e;
+        cin>>n;
+        for(int i=0;i<n;i++)
+            {
+                cin>>e;
+                st.push(e);
+            }
+
+         reversestack(st);
+
+        while(!st.empty())
+            {
+                cout<<st.top()<<" ";
+                st.pop();
+            }
+
+        return 0; 
+    }