C++/String/string subscript indexer

Accessing characters in a string

<source lang="cpp">

1. include <iostream>
2. include <string>
3. include <cctype>

using std::cout; using std::cin; using std::endl; using std::string; int main() {

 string text = "asdffdsaasdf";

 int vowels = 0;              
 int consonants = 0;          
 for(int i = 0 ; i < text.length() ; i++)
   if(std::isalpha(text[i]))  
     switch(std::tolower(text[i])) {
       case "a": case "e": case "i":
       case "o": case "u":
         vowels++;
         break;
       default:
         consonants++;
     }
 cout << "Your input contained "
      << vowels     << " vowels and "
      << consonants << " consonants."
      << endl;
 return 0;

} /* Your input contained 3 vowels and 9 consonants.

*/        
   
 </source>

Modify char in a string by indexer

<source lang="cpp">

1. include <iostream>

using std::cout; using std::endl;

1. include <string>

using std::string; int main() {

  string string1( "cat" );
  string string2;
  string string3;
  string2 = string1;
  string3.assign( string1 );
  
  cout << "string1: " << string1 << "\nstring2: " << string2
     << "\nstring3: " << string3 << "\n\n";
  string2[ 0 ] = string3[ 2 ] = "r";
  cout << "string1: " << string1 << "\nstring2: " << string2 << "\nstring3: ";

  return 0;

} /* string1: cat string2: cat string3: cat string1: cat string2: rat string3:

*/        
   
 </source>

switch statement based on char value

<source lang="cpp">

1. include <iostream>
2. include <string>
3. include <cctype>

using std::cout; using std::cin; using std::endl; using std::string; int main() {

 string text = "asdffdsaasdf";

 int vowels = 0;              
 int consonants = 0;          
 for(int i = 0 ; i < text.length() ; i++)
   if(std::isalpha(text[i]))  
     switch(std::tolower(text[i])) {
       case "a": case "e": case "i":
       case "o": case "u":
         vowels++;
         break;
       default:
         consonants++;
     }
 cout << "Your input contained "
      << vowels     << " vowels and "
      << consonants << " consonants."
      << endl;
 return 0;

} /* Your input contained 3 vowels and 9 consonants.

*/
       
   
 </source>

Tests whether a string is a palindrome

<source lang="cpp">

1. include <iostream>
2. include <string>
3. include <vector>

using namespace std; bool is_palindrome(string s) {

  if (s.length() <= 1) 
    return true;
  char first = s[0];
  char last = s[s.length() - 1];
  if (first == last){
     string subString = s.substr(1, s.length() - 2);
     return is_palindrome(subString);
  }
  else
     return false;

} int main() {

  cout << "Enter a string: ";
  string input;
  getline(cin, input);
  if (!is_palindrome(input)) 
    cout << "false";
  
  return 0;

}

 </source>