C++ || Snippet – Array Based Custom Template Stack Sample Code
This page will consist of sample code for a custom array based template stack.
REQUIRED KNOWLEDGE FOR THIS SNIPPET
Classes
Template Classes - What Are They?
Stacks
LIFO - What Is It?
#include < stack>
This template class is a custom duplication of the Standard Template Library (STL) stack class. Whether you like building your own data structures, you simply do not like to use any inbuilt functions, opting to build everything yourself, or your homework requires you make your own data structure, this sample code is really useful. I feel its beneficial building functions such as this, that way you better understand the behind the scene processes.
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// ============================================================================ // Author: K Perkins // Date: Mar 22, 2012 // Taken From: http://programmingnotes.org/ // File: ClassStackType.h // Description: This is a class which implements various functions // demonstrating the use of a stack. // ============================================================================ #include <iostream> template <class ItemType> class StackType { public: StackType(); /* Function: constructor initializes class variables Precondition: none Postcondition: defines private variables */ bool IsEmpty(); /* Function: Determines whether the stack is empty Precondition: Stack has been initialized Postcondition: Function value = (stack is empty) */ bool IsFull(); /* Function: Determines whether the stack is full Precondition: Stack has been initialized Postcondition: Function value = (stack is full) */ int Size(); /* Function: Return the current size of the stack Precondition: Stack has been initialized Postcondition: If (stack is full) exception FullStack is thrown else newItem is at the top of the stack */ void MakeEmpty(); /* Function: Empties the stack Precondition: Stack has been initialized Postcondition: Stack is empty */ void Push(ItemType newItem); /* Function: Adds newItem to the top of the stack Precondition: Stack has been initialized Postcondition: If (stack is full) exception FullStack is thrown else newItem is at the top of the stack */ ItemType Pop(); /* Function: Returns & then removes top item from the stack Precondition: Stack has been initialized Postcondition: If (stack is empty) exception EmptyStack is thrown else top element has been removed from the stack */ ItemType Top(); /* Function: Returns the top item from the stack Precondition: Stack has been initialized Postcondition: If (stack is empty) exception EmptyStack is thrown else top element has been removed from the stack */ ~StackType(); /* Function: destructor deallocates class variables Precondition: none Postcondition: deallocates private variables */ private: int top; // indicates which element is on top int MAX_ITEMS; // max number of items in the list ItemType stack[200]; // array holding the popped/pushed data }; //========================= Implementation ================================// template<class ItemType> StackType<ItemType>::StackType() { top = -1; MAX_ITEMS = 200; }// End of StackType template<class ItemType> bool StackType<ItemType>::IsEmpty() { return (top == -1); }// End of IsEmpty template<class ItemType> bool StackType<ItemType>::IsFull() { return (top==(MAX_ITEMS-1)); }// End of IsFull template<class ItemType> int StackType<ItemType>::Size() { if(IsEmpty()) { std::cout<<"nSTACK EMPTYn"; return('?'); } return top+1; }// End of Size template<class ItemType> void StackType<ItemType>::MakeEmpty() { top = -1; }// End of MakeEmpty template<class ItemType> void StackType<ItemType>::Push(ItemType newItem) { if(IsFull()) { std::cout<<"nSTACK FULLn"; return; } stack[++top]=newItem; }// End of Push template<class ItemType> ItemType StackType<ItemType>::Pop() { if(IsEmpty()) { std::cout<<"nSTACK EMPTYn"; return('?'); } return(stack[top--]); }// End of Pop template<class ItemType> ItemType StackType<ItemType>::Top() { if(IsEmpty()) { std::cout<<"nSTACK EMPTYn"; return('?'); } return(stack[top]); }// End of Top template<class ItemType> StackType<ItemType>::~StackType() { top = -1; }// http://programmingnotes.org/ |
QUICK NOTES:
The highlighted lines are sections of interest to look out for.
The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.
===== DEMONSTRATION HOW TO USE =====
Use of the above template class is the same as its STL counterpart. Here is a sample program demonstrating its use.
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#include <iostream> #include "ClassStackType.h" using namespace std; int main() { // declare variables StackType<char> charStack; StackType<int> intStack; StackType<float> floatStack; // ------ Char Example ------// char charArry[]="My Programming Notes"; int counter=0; while(charArry[counter]!=' ') { charStack.Push(charArry[counter]); ++counter; } cout<<"charStack has "<<charStack.Size()<<" items in itn" <<"and contains the text: "<<charArry<<" backwards "; while(!charStack.IsEmpty()) { cout<<charStack.Pop(); } cout<<endl; // ------ Int Example ------// int intArry[]={1,2,3,4,5,6,7,8,9}; counter=0; while(counter<9) { intStack.Push(intArry[counter]); ++counter; } cout<<"intStack has "<<intStack.Size()<<" items in it.n" <<"The sum of the numbers in the stack is: "; counter=0; while(!intStack.IsEmpty()) { counter+=intStack.Pop(); } cout<<counter<<endl; // ------ Float Example ------// float floatArry[]={1.6,2.8,3.9,4.4,5.987,6.23,7.787,8.99,9.6,1.540}; float sum=0; counter=0; while(counter<10) { floatStack.Push(floatArry[counter]); ++counter; } cout<<"floatStack has "<<floatStack.Size()<<" items in it.n" <<"The sum of the numbers in the stack is: "; while(!floatStack.IsEmpty()) { sum+=floatStack.Pop(); } cout<<sum<<endl; }// http://programmingnotes.org/ |
Once compiled, you should get this as your output
charStack has 20 items in it
and contains the text: My Programming Notes
backwards setoN gnimmargorP yMintStack has 9 items in it.
The sum of the numbers in the stack is: 45floatStack has 10 items in it.
The sum of the numbers in the stack is: 52.834
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