stack implementation

1#include <iostream>
2using namespace std;
3int stack[100], n=100, top=-1;
4void push(int val) {
5   if(top>=n-1)
6   cout<<"Stack Overflow"<<endl;
7   else {
8      top++;
9      stack[top]=val;
10   }
11}
12void pop() {
13   if(top<=-1)
14   cout<<"Stack Underflow"<<endl;
15   else {
16      cout<<"The popped element is "<< stack[top] <<endl;
17      top--;
18   }
19}
20void display() {
21   if(top>=0) {
22      cout<<"Stack elements are:";
23      for(int i=top; i>=0; i--)
24      cout<<stack[i]<<" ";
25      cout<<endl;
26   } else
27   cout<<"Stack is empty";
28}
29int main() {
30   int ch, val;
31   cout<<"1) Push in stack"<<endl;
32   cout<<"2) Pop from stack"<<endl;
33   cout<<"3) Display stack"<<endl;
34   cout<<"4) Exit"<<endl;
35   do {
36      cout<<"Enter choice: "<<endl;
37      cin>>ch;
38      switch(ch) {
39         case 1: {
40            cout<<"Enter value to be pushed:"<<endl;
41            cin>>val;
42            push(val);
43            break;
44         }
45         case 2: {
46            pop();
47            break;
48         }
49         case 3: {
50            display();
51            break;
52         }
53         case 4: {
54            cout<<"Exit"<<endl;
55            break;
56         }
57         default: {
58            cout<<"Invalid Choice"<<endl;
59         }
60      }
61   }while(ch!=4);
62   return 0;
63}

1#include <stdio.h>
2
3int MAXSIZE = 8;       
4int stack[8];     
5int top = -1;            
6
7int isempty() {
8
9   if(top == -1)
10      return 1;
11   else
12      return 0;
13}
14   
15int isfull() {
16
17   if(top == MAXSIZE)
18      return 1;
19   else
20      return 0;
21}
22
23int peek() {
24   return stack[top];
25}
26
27int pop() {
28   int data;
29	
30   if(!isempty()) {
31      data = stack[top];
32      top = top - 1;   
33      return data;
34   } else {
35      printf("Could not retrieve data, Stack is empty.\n");
36   }
37}
38
39int push(int data) {
40
41   if(!isfull()) {
42      top = top + 1;   
43      stack[top] = data;
44   } else {
45      printf("Could not insert data, Stack is full.\n");
46   }
47}
48
49int main() {
50   // push items on to the stack 
51   push(3);
52   push(5);
53   push(9);
54   push(1);
55   push(12);
56   push(15);
57
58   printf("Element at top of the stack: %d\n" ,peek());
59   printf("Elements: \n");
60
61   // print stack data 
62   while(!isempty()) {
63      int data = pop();
64      printf("%d\n",data);
65   }
66
67   printf("Stack full: %s\n" , isfull()?"true":"false");
68   printf("Stack empty: %s\n" , isempty()?"true":"false");
69   
70   return 0;
71}

1typedef struct Nodo{
2   Elem val;
3   struct Nodo *next;
4} *Stack;
5Stack Empty(){return NULL;}
6bool IsEmpty(Stack a){return a==NULL;}
7Elem Top(Stack a){return a->val;} 
8Stack Pop(Stack l){return l->next;}
9Stack Push(Elem x,Stack res){
10    Stack nuevo=(Stack)malloc(sizeof(struct Nodo));
11    nuevo->val=x;
12    nuevo->next=res;
13    return nuevo;
14}

1#include <iostream>
2using namespace std;
3int top = -1; //Globally defining the value of top as the stack is empty
4
5    void push (int stack[ ] , int x , int n)
6    {
7        if ( top == n-1 )       //If the top position is the last of position of the stack, this means that the stack is full.
8        {
9            cout << "Stack is full.Overflow condition!" ;
10        }
11        else
12        {
13            top = top +1 ;            //Incrementing the top position 
14            stack[ top ] = x ;       //Inserting an element on incremented position  
15        }
16    }
17    bool isEmpty ( )
18    {
19        if ( top == -1 )  //Stack is empty
20            return true ; 
21        else
22            return false;
23    }
24    void pop ( ) 
25    {
26
27        if( isEmpty ( ) )
28        {
29            cout << "Stack is empty. Underflow condition! " << endl ;
30        }
31        else    
32        {
33             top = top - 1 ; //Decrementing top’s position will detach last element from stack            
34        }
35    }
36    int size ( )
37    {
38        return top + 1;
39    }
40    int topElement (int stack[])
41    {
42        return stack[ top ];
43    }
44    //Let's implement these functions on the stack given above 
45
46    int main( )
47    {
48        int stack[ 3 ];
49        // pushing element 5 in the stack .
50        push(stack , 5 , 3 ) ;
51
52        cout << "Current size of stack is " << size ( ) << endl ;
53
54        push(stack , 10 , 3);
55        push (stack , 24 , 3) ;
56
57        cout << "Current size of stack is " << size( ) << endl ;
58
59        //As the stack is full, further pushing will show an overflow condition.
60        push(stack , 12 , 3) ;
61
62        //Accessing the top element
63        cout << "The current top element in stack is " << topElement(stack) << endl;
64
65        //Removing all the elements from the stack
66        for(int i = 0 ; i < 3;i++ )
67            pop( );
68        cout << "Current size of stack is " << size( ) << endl ;
69
70        //As the stack is empty , further popping will show an underflow condition.
71        pop ( );  
72
73    }