44 lines
1.1 KiB
C++
44 lines
1.1 KiB
C++
#include "TStack.h"
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#include <iostream>
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// Time complexity O(1) - always append to the end of the array and use that as the top of the stack
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// Space complexity O(1) - no need to save helper variables, just place on top of existing, size-static stack
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void TStack::Push(const int item)
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{
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if (top >= MAX_SIZE)
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throw std::overflow_error("Stack overflow");
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stack[top++] = item;
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}
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// Time and space complexity both O(1) - Only works with the top element so if you have
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// 5 or 500 elements in the stack the result will be the same
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// Only returns and removes top element
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int TStack::Pop()
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{
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if (top == 0)
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throw std::underflow_error("Stack underflow");
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return stack[--top];
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}
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// Time and space complexity O(1) - only returns the top element
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int TStack::Peek() const
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{
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if (top == 0)
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throw std::underflow_error("Stack underflow");
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return stack[top - 1];
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}
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// O(1) for both, checks to see if the stack is empty or not
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// doesn't determine exact amount - just makes sure it has one
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bool TStack::IsEmpty() const
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{
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return top == 0;
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}
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