Create RevStringInStack.cpp

Cpp/RevStringInStack.cpp

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+// C++ program to reverse a string using stack
+#include <bits/stdc++.h>
+using namespace std;
+
+// A structure to represent a stack
+class Stack {
+public:
+	int top;
+	unsigned capacity;
+	char* array;
+};
+
+// function to create a stack of given
+// capacity. It initializes size of stack as 0
+Stack* createStack(unsigned capacity)
+{
+	Stack* stack = new Stack();
+	stack->capacity = capacity;
+	stack->top = -1;
+	stack->array
+		= new char[(stack->capacity * sizeof(char))];
+	return stack;
+}
+
+// Stack is full when top is equal to the last index
+int isFull(Stack* stack)
+{
+	return stack->top == stack->capacity - 1;
+}
+
+// Stack is empty when top is equal to -1
+int isEmpty(Stack* stack) { return stack->top == -1; }
+
+// Function to add an item to stack.
+// It increases top by 1
+void push(Stack* stack, char item)
+{
+	if (isFull(stack))
+		return;
+	stack->array[++stack->top] = item;
+}
+
+// Function to remove an item from stack.
+// It decreases top by 1
+char pop(Stack* stack)
+{
+	if (isEmpty(stack))
+		return -1;
+	return stack->array[stack->top--];
+}
+
+// A stack based function to reverse a string
+void reverse(char str[])
+{
+	// Create a stack of capacity
+	// equal to length of string
+	int n = strlen(str);
+	Stack* stack = createStack(n);
+
+	// Push all characters of string to stack
+	int i;
+	for (i = 0; i < n; i++)
+		push(stack, str[i]);
+
+	// Pop all characters of string and
+	// put them back to str
+	for (i = 0; i < n; i++)
+		str[i] = pop(stack);
+}
+
+// Driver code
+int main()
+{
+	char str[] = "GeeksQuiz";
+
+	reverse(str);
+	cout << "Reversed string is " << str;
+
+	return 0;
+}
+
+// This code is contributed by rathbhupendra