c++ - I am not able to run this code on Code::blocks IDE but works fine online...!!can anyone tell me what modifications i should to get it working on IDE? -

by using typdef have defines stack, code blocks gives me error while call object.

#include <iostream> using namespace std;  struct stack {     int data[20];     int top; }; 

in class, stack *s called , when run program gives error "s" maybe used uninitialised. whereas have initilaised using constructor.

class stackop { public:      stack *s;      stackop()     {         s->top= -1; //constructor giving error.     }      bool stack_empty();     bool stack_full();     void push();     void pop();     void display(); };  bool stackop::stack_empty() {     if(s->top == -1)     {         return 1;     }     else     {         return 0;     } }  bool stackop::stack_full() {     if(s->top == 19)     {         return 1;     }     else     {         return 0;     } }   void stackop::push() {      if(!stack_full())     {         s->top=s->top + 1;         cout<<"\n enter element: ";         cin>>s->data[s->top];     }     else     {         cout<<"\n stack full";     } }  void stackop::pop() {     if(!stack_empty())     {         cout<<"\n value deleted or poped "<<s->data[s->top];         s->top=s->top-1;     }     else     {         cout<<"\n stack empty";     } }  void stackop::display() {     cout<<"\n stack follows...";     for(int i=s->top; i>=0; i--)     {         cout<<"\n"<<s->data[i];     } } 

also code runs fine on cpp.sh terminates terminal of code blocks returning garbage value.

int main() {     int y;     char ch;      stackop s1;          {         cout<<"\n 1. push.";         cout<<"\n 2. pop.";         cout<<"\n 3. display stack.";         cout<<"\n\n enter choice :: ";         cin>>y;          switch(y)         {         case 1:             s1.push();             break;         case 2:             s1.pop();             break;         case 3:             s1.display();             break;         }          cout<<"\n want continue? : ";         cin>>ch;      } while(ch=='y');      return 0; } 

make small change in program work fine

stack *s = new stack; 

by doing above change ,program worked in code block ide