Merge pull request codemistic#581 from DharmaWarrior/main

Contributed implementation of Stacks

Author: gantavyamalviya

Stack/reversing_a_string_using_stack.cpp

@@ -0,0 +1,56 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+/*class Stack{
+ private:
+ char *arr;
+ int size;
+ int top=-1;
+ public:
+
+ Stack(int n){
+ size=n;
+ arr=new char[size];
+ }
+
+ void push(string t){
+ 
+ if(top==size-1){
+ cout<<"stack overflow"<<endl;
+ }else{
+ top++;
+ arr[top]=t[i];
+ }
+ }
+ void display(){
+ for(int i=arr.size()-1;i>=0;i--){
+ cout<<arr[i];
+ }
+ }
+}*/
+
+int main(){
+ 
+ stack<char> s;
+ 
+ string n =" Saar";
+ 
+ for(int i=0;i<n.size();i++){
+ char ch=n[i];
+ s.push(ch);
+ }
+ 
+ string mac = "";
+ 
+ while(!s.empty()){
+ 
+ char new1=s.top();
+ mac.push_back(new1);
+
+ s.pop(); 
+ }
+
+ cout<<"answer is"<<mac<<endl;
+
+ return 0;
+}

Stack/stack_implementation_using_Linked_list.cpp

@@ -0,0 +1,67 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+class Node{
+ public:
+ int data;
+ Node *next;
+};
+ 
+class Stack{
+ private:
+ Node *top;
+ public:
+ Stack(){top=NULL;}
+
+ void push(int x);
+ int pop();
+ void display();
+};
+
+void Stack::push(int x){
+ Node *t=new Node;
+ if(t==NULL)
+ cout<<"Stack is Flow"<<endl;
+ else{
+ t->data=x;
+ t->next=top;
+ top=t;
+ }
+}
+
+int Stack::pop(){
+ int x=-1;
+ if(top==NULL){
+ cout<<"Stack is Emplty"<<endl;
+ }else{
+ x=top->data;
+ Node *t=top;
+ top=top->next;
+ delete t;
+
+ }
+ return x;
+}
+
+void Stack::display(){
+ Node *p=top;
+ while(p!=NULL){
+ cout<<p->data<<" ";
+ p=p->next;
+ }
+ cout<<endl;
+}
+
+int main(){
+ Stack stk;
+
+ stk.push(10);
+ stk.push(20);
+ stk.push(30);
+
+ stk.display();
+ cout<<stk.pop()<<endl;
+ stk.display();
+
+ return 0;
+}

Stack/stack_implementation_using_array.c

@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <stdlib.h>
+struct Stack
+{
+ int size;
+ int top;
+ int *S;
+};
+void create(struct Stack *st)
+{
+ printf("Enter Size");
+ scanf("%d", &st->size);
+ st->top = -1;
+ st->S = (int *)malloc(st->size * sizeof(int));
+}
+void Display(struct Stack st)
+{
+ int i;
+ for (i = st.top; i >= 0; i--)
+ printf("%d ", st.S[i]);
+ printf("\n");
+}
+void push(struct Stack *st, int x)
+{
+ if (st->top == st->size - 1)
+ printf("Stack overflow\n");
+ else
+ {
+ st->top++;
+ st->S[st->top] = x;
+ }
+}
+int pop(struct Stack *st)
+{
+ int x = -1;
+ if (st->top == -1)
+ printf("Stack Underflow\n");
+ else
+ {
+ x = st->S[st->top--];
+ }
+ return x;
+}
+int peek(struct Stack st, int index)
+{
+ int x = -1;
+ if (st.top - index + 1 < 0)
+ printf("Invalid Index \n");
+ x = st.S[st.top - index + 1];
+ return x;
+}
+int isEmpty(struct Stack st)
+{
+ if (st.top == -1)
+ return 1;
+ return 0;
+}
+int isFull(struct Stack st)
+{
+ return st.top == st.size - 1;
+}
+int stackTop(struct Stack st)
+{
+ if (!isEmpty(st))
+ return st.S[st.top];
+ return -1;
+}
+int main()
+{
+ struct Stack st;
+ create(&st);
+ push(&st, 10);
+ push(&st, 20);
+ push(&st, 30);
+ push(&st, 40);
+ printf("%d \n", peek(st, 2));
+ Display(st);
+ return 0;
+}

Stack/stack_implementation_using_array.cpp

@@ -0,0 +1,69 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class stack1
+{
+private:
+ int size;
+ int top;
+ vector<int> s; 
+
+public:
+ stack1(int n){
+ size=n;
+ s.resize(n);
+ top=-1;
+ }
+
+ void display()
+ {
+ int i;
+ for (i = top; i >= 0; i--)
+ {
+ cout<<s[i]<<endl;
+ }
+ }
+
+ void push(int x)
+ {
+ if (top == size - 1)
+ {
+ cout<<"Stack Overflow"<<endl;
+ }
+ else
+ {
+ top++;
+ s[top] = x;
+ }
+ }
+
+ int pop()
+ {
+ int x = -1;
+ if (top == -1)
+ {
+ cout<<"Stack Underflow"<<endl;
+ }
+ else
+ {
+ x = s[top--];
+ }
+ return x;
+ }
+ };
+
+int main()
+{
+ stack1 st(4);
+ 
+
+ st.push(10);
+ st.push(20);
+ st.push(30);
+ st.push(40);
+ st.push(50);
+ st.push(60);
+ 
+ st.display();
+ return 0;
+}