重复的字符，其第一次出现在最左边

String = “Tutorialspoint”

Output = The repeating character is “t”

String = “abcaabb”

Output = The repeating character is “a”

String = “programming”

Output = No repeating character.

find(char)

string_name.length()

#include 
#include 

using namespace std;

char findLeftmostRepeatedChar(string s){
   unordered_map charMap;

   // Traverse the string from left to right
   for (int x = 0; x < s.length(); x++) {
      char ch = s[x];

      // If the character is already in the map, return it
      if (charMap.find(ch) != charMap.end()) {
         return ch;
      } else {
         // Otherwise, add the character to the map
         charMap[ch] = x;
      }
   }
   // If no character is repeated, return '\0'
   return '\0';
}
int main() {
   string s = "tutorialspoint";
   char leftmostRepeatedChar = findLeftmostRepeatedChar(s);

   if (leftmostRepeatedChar != '\0'){
      cout << "The leftmost repeated character in "" << s << "" is '" << leftmostRepeatedChar << "'" << endl;
   } 
   else{
      cout << "There are no repeated characters in "" << s << """ << endl;
   }
   return 0;
}

The leftmost repeated character in  << s <<  is 't'