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Applications of Stack
Function Call Management:
Stacks are used to manage function calls in programming languages. When a function is called, its data is pushed onto the stack, and when it returns, the data is popped off. This ensures that each function call is handled in the correct order.
// Function call stack example
void functionA() {
functionB();
}
void functionB() {
// Some operations
}
int main() {
functionA();
return 0;
}
Explanation:
In this code, when functionA is called, it pushes its context onto the stack. Then, functionB is called, and its context is also pushed. Once functionB completes, it is popped off the stack, and control returns to functionA.
Expression Evaluation:
Infix to Postfix Conversion:
Stacks are used to convert infix expressions (like A + B) into postfix expressions (like AB+), which are easier for computers to evaluate.
// Pseudocode for converting infix to postfix
infixToPostfix(expression) {
for each character in expression {
if operand, add to output;
else if '(', push to stack;
else if ')', pop from stack to output until '(';
else operator, pop from stack to output while precedence is higher;
}
while stack not empty, pop to output;
}
Explanation:
This pseudocode demonstrates how an infix expression is processed using a stack to produce a postfix expression, which can be evaluated using a simple algorithm.
Undo Mechanism in Editors:
Text Editor Undo:
Stacks are used in text editors to implement the undo feature. Each operation performed by the user is pushed onto a stack, and when an undo is requested, the last operation is popped and reversed.
// Pseudocode for undo mechanism
performOperation(operation) {
stack.push(operation);
}
undo() {
if (!stack.isEmpty()) {
operation = stack.pop();
reverseOperation(operation);
}
}
Explanation:
The stack keeps track of all operations, and the most recent one can be undone by popping it from the stack and reversing it.
Backtracking Algorithms:
Maze Solving:
Stacks are used in backtracking algorithms to solve problems like maze navigation. The stack keeps track of the path, and when a dead end is reached, it backtracks to the last decision point.
// Pseudocode for maze solving
solveMaze(maze) {
stack.push(startPoint);
while (!stack.isEmpty()) {
current = stack.pop();
if (current is exit) return path;
for each neighbor of current {
if (neighbor is not visited) {
mark visited;
stack.push(neighbor);
}
}
}
}
Explanation:
The stack helps in exploring paths in the maze and backtracking when necessary until the exit is found.
Browser History Navigation:
Navigating Back:
Stacks are used to manage the history of pages visited in a web browser. When a user navigates to a new page, the current page is pushed onto the stack, and the back button pops the stack to return to the previous page.
// Pseudocode for browser back navigation
visitPage(url) {
historyStack.push(currentPage);
currentPage = url;
}
goBack() {
if (!historyStack.isEmpty()) {
currentPage = historyStack.pop();
}
}
Explanation:
The stack allows users to navigate backward through their browsing history by storing previously visited pages.
