Problem with OLED Display Voltages (String Command) using transmitter and Receiver

This code makes no sense to me, for example

      for (byte i = 0; i <= 35; i++) {
        char c = inputString[i];
        if (c == 'V') {
          int index = inputString.indexOf("V");

The for-loop and if statement seem to be searching through the string for a "V" character, one position at a time. But then you use .indexOf(), which will find the "V" in a single step, so why bother with the for-loop? It is repeating code 35 times over when it needs to run only once.