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Reverse a String

Certification: Basic Level Accuracy: 54.74% Submissions: 95 Points: 10

Write a C++ program that reverses a string using pointers.

Example 1
     
  • Input: string = "hello"
    •  
  • Output: "olleh"
    •  
  • Explanation: 
       
    • Step 1: Initialize pointers to the start and end of the string.
      •  
    • Step 2: Swap characters at start and end positions.
      •  
    • Step 3: Move start pointer forward and end pointer backward.
      •  
    • Step 4: Repeat steps 2-3 until pointers meet in the middle.
      •  
    •
Example 2
     
  • Input: string = "world"
    •  
  • Output: "dlrow"
    •  
  • Explanation: 
       
    • Step 1: Initialize pointers to the start and end of the string.
      •  
    • Step 2: Swap characters at start and end positions.
      •  
    • Step 3: Move start pointer forward and end pointer backward.
      •  
    • Step 4: Repeat steps 2-3 until pointers meet in the middle.
      •  
    •
Constraints
     
  • 1 ≤ string length ≤ 10^6
    •  
  • Use pointers to reverse the string
    •  
  • Time Complexity: O(n) where n is the length of the string
    •  
  • Space Complexity: O(1)
    •
StringsPointers and ReferencesCapgeminiEY
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Hint
Solution

Solution Hints

    
  
  • Use two pointers, one at the beginning and one at the end of the string.
    • 
  
  • Swap the characters at these pointers and move them towards the center.
    • 
  
  • Stop when the pointers meet or cross each other.
    •

Steps to solve by this approach:

 Step 1: Define a function reverse_string that takes a character pointer as parameter.

 Step 2: Create two pointers - one pointing to the start of string, another to the end.

 Step 3: While the start pointer is less than the end pointer, swap the characters they point to.

 Step 4: Increment the start pointer and decrement the end pointer after each swap.

 Step 5: In main, declare a character array with a string value.

 Step 6: Call reverse_string with this array.

 Step 7: Print the reversed string to verify the operation.

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