如何在交换机情况下将数组转换为int？

Question

我对我的项目有疑问。我仍然是这个领域的初学者。我想制作一个可以过滤第一个和第二个字符的程序。我已经尝试了很多，但结果仍然不符合我的期望。这是我所做的代码：

int i;                      // counter i
int inByte =0;
int numByte =0;
int value = 0;
char*arrayData= "0,1,2";

String stringA = "";

float reading = 0;

void setup() {    // initialize serial communications at 9600 bps:
  Serial.begin(9600); 
  analogReference (INTERNAL); 
  pinMode(13, OUTPUT);
  clearBuff();
}

void loop() {
  if (Serial.available()) {
  numByte = Serial.available();
  for (int i =0; i < numByte; i++){
  inByte = Serial.read();
    }
      if (inByte == 13){ //inByte is collected until carriage return;   
        if (stringA.substring(0,1)== "F"){ //if the first character of stringA is  "F", this condition is true and ledShort will be operate;
        ledShort();  

        int value = atoi(arrayData);
        if(value = stringA.substring(0,2).toInt()){ //if the second character of stringA is 0,1,2 (according arrayData) this condition is true. Else, it is false;
          switch(value){        
            case 1:
              value = (arrayData[1]); // value = 0
              break;
           case 2:
              value = (arrayData[2]); // value = 1
               break;
           case 3:
              value = (arrayData[3]); // value = 2
              break;
           default:
              clearBuff;
              Serial.print("");
              break;
            } 
           }
          }
      Serial.println(stringA.substring(0,1));
      Serial.println(stringA.substring(0,2).toInt());
      Serial.println(value);
      Serial.println(stringA);
      stringA = "";
      clearBuff();
      }  

     else{ 
      stringA += char(inByte);
      if (stringA.length() > 15){
        clearBuff();
        stringA = "";
        }
      }
   }
}


void ledShort() {
  digitalWrite(13, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(50);              // wait for a second
  digitalWrite(13, LOW);    // turn the LED off by making the voltage LOW
  }

void clearBuff(){          // flush chars in serial buffer
  while (Serial.available() > 0 ){
    inByte = Serial.read();
    }
  }

第一个字符（"F"）没有问题，但此程序无法识别数字0,1,2。

在串行监视器上键入F0时，会显示F,0,0,F1。如果F1也相同F,0,0,F1。我想要F1 = F,1,1,F2。