31 lines
1.3 KiB
Markdown
Executable File
31 lines
1.3 KiB
Markdown
Executable File
# Overview
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- A stack is ta LIFO list. Meaning "last in first out"
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- Access is allowed only from one end of the stack
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- adding an item is called pulsing the stack
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- retrieving an item is called popping the stack
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# Typical Uses
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- Parentheses matching; ()), or (())
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- compiler's syntax check for matching braces is implemented by using stack
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- The simplest application of a stack is to reverse a word.
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- You push a given word to stack - letter by letter - and then pop letters from the stack.
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- Another application is an "undo" mechanism in text editors;
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-this operation is accomplished by keeping all text changes in a stack
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# Parenthesis Count
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- Methodology (logical steps to solve the problem):
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- scan expression from left to right;
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- when a left parenthesis is encountered, add its position to the stack;
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- when a right parenthesis is encountered, remove matching position from stack (more example in a moment).
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# Try-catch-throw
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- When you enter a try block, push the address of this block onto a stack.
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\
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- When an exception is thrown, pop the try block that is at the top of the stack; if the stack is empty, terminate the program.
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- If the popped try block has no matching catch block, go back to the previous step.
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- If the popped try block has a matching catch block, execute the matching catch block.
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