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Concatenate Two Strings

Certification: Basic Level Accuracy: 73.33% Submissions: 15 Points: 10

Write a C++ program that concatenates two strings using pointers. The program should take two strings as input and return a new string that concatenates the two input strings.

Example 1
     
  • Input: string1 = "Hello", string2 = "World"
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  • Output: "HelloWorld"
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  • Explanation: 
       
    • Step 1: Determine the length of both input strings.
      •  
    • Step 2: Allocate memory for the result string (length of string1 + length of string2 + 1 for null terminator).
      •  
    • Step 3: Use pointers to copy characters from string1 to the result string.
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    • Step 4: Use pointers to append characters from string2 to the result string.
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    • Step 5: Add null terminator at the end of the result string.
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    •
Example 2
     
  • Input: string1 = "C++", string2 = "Programming"
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  • Output: "C++Programming"
    •  
  • Explanation: 
       
    • Step 1: Determine the length of both input strings.
      •  
    • Step 2: Allocate memory for the result string (length of string1 + length of string2 + 1 for null terminator).
      •  
    • Step 3: Use pointers to copy characters from string1 to the result string.
      •  
    • Step 4: Use pointers to append characters from string2 to the result string.
      •  
    • Step 5: Add null terminator at the end of the result string.
      •  
    •
Constraints
     
  • 1 ≤ len(string1) ≤ 10^3
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  • 1 ≤ len(string2) ≤ 10^3
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  • Strings contain printable ASCII characters
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  • Time Complexity: O(n + m) where n and m are the lengths of the two strings
    •  
  • Space Complexity: O(n + m) for storing the result
    •
StringsPointers and ReferencesCognizantDropbox
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Hint
Solution

Solution Hints

    
  
  • Use pointers to traverse both strings.
    • 
  
  • Allocate memory for the concatenated string dynamically.
    • 
  
  • Copy characters from both strings to the new string using pointers.
    •

Steps to solve by this approach:

 Step 1: Define a function concatenateStrings that takes two constant character pointers as parameters.

 Step 2: Calculate the lengths of both input strings.

 Step 3: Dynamically allocate memory for the result, big enough to hold both strings plus the null terminator.

 Step 4: Create a pointer to track our position in the result string.

 Step 5: Copy characters from the first string to the result one by one, advancing both pointers.
 Step 6: Copy characters from the second string to the result one by one, advancing both pointers.

 Step 7: Add the null terminator at the end of the result.

 Step 8: Return the pointer to the result string.

 Step 9: In main, call concatenateStrings with two strings, print the result, and free the allocated memory.

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