C++ program: replace character at specific index

A string is a set of characters. We can also call them character arrays. considering A character array consisting of strings with the specified index and value. sometimes We can make some modifications to the string, one of the modifications is to replace characters By providing a specific index. In this article we will see how to replace a character from a specific index inside a string using C .

grammar

String_variable[ <given index> ] = <new character>

In C, we can access string characters using indexes. The code used here to replace a character is At the specified index position, we only need to assign the position to a new character character as shown in the syntax. Let us see the algorithm for a better understanding.

algorithm

• Get the string s, specify the index i, and a new character c
• If index i is positive and its value does not exceed the string size, then
  • s[ i ] = c
  • return s
The Chinese translation of
• otherwise is: Otherwise
  • Return s without changing anything
• end if

Example

#include <iostream>
using namespace std;
string solve( string s, int index, char new_char){
   
   // replace new_char with the existing character at s[index]
   if( index >= 0 && index < s.length() ) {
      s[ index ] = new_char;
      return s;
   } else {
      return s;
   }
}
int main(){
   string s = "This is a sample string.";
   cout << "Given String: " << s << endl;
   cout << "Replace 8th character with X." << endl;
   s = solve( s, 8, 'X' );
   cout << "Updated String: " << s << endl;
   cout << "Replace 12th character with ?." << endl;
   s = solve( s, 12, '?' );
   cout << "Updated String: " << s << endl;
}

Output

Given String: This is a sample string.
Replace 8th character with X.
Updated String: This is X sample string.
Replace 12th character with ?.
Updated String: This is X sa?ple string.

in conclusion

Replacing characters at a specified index is simple enough in C . C strings are mutable, so we can change them directly. In some other languages ​​like java, the strings are not mutable. There is no range in which characters can be replaced by assigning new characters In such cases, a new string needs to be created. A similar will happen if we define strings as In C language, we can use character pointers. In our example, we define a function to replace a Returns the character at the given index position. If the given index is out of range, it will return string and it will remain unchanged.

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