convert from hex to decimal Arduino

问题:

I am extracting the weight of a Reach Stacker, for the moment this is my result:

get data from ID:
18FFF227
2 1 F0 3C 0 0 1 0

what I need is to take F0 3C 0 0 and change it to 0 0 3C F0 then convert it to number to decimal.

 003CF0 = 15600

according to this page: enter link description here this would be my number in decimal 15600

this my code :

    #include <SPI.h>
    #include "mcp_can.h"
    #include <SoftwareSerial.h>

    SoftwareSerial mySerial (3,2);
    // the cs pin of the version after v1.1 is default to D9
    // v0.9b and v1.0 is default D10
    const int SPI_CS_PIN = 9;

    MCP_CAN CAN(SPI_CS_PIN);                                    // Set CS pin

    void setup()
    {
        Serial.begin(9600);
        mySerial.begin(9600);

    START_INIT:

        if(CAN_OK == CAN.begin(CAN_500KBPS))                   // init can bus : baudrate = 500k
        {
            Serial.println("CAN BUS Shield init ok!");
        }
        else
        {
            Serial.println("CAN BUS Shield init fail");
            Serial.println("Init CAN BUS Shield again");
            delay(100);
            goto START_INIT;
        }
    }


    void loop()
    {
        unsigned char len = 0;
        unsigned char buf[8];

        if(CAN_MSGAVAIL == CAN.checkReceive())            // check if data coming
        {
            CAN.readMsgBuf(&len, buf);    // read data,  len: data length, buf: data buf

        //     unsigned char canId = CAN.getCanId();
          unsigned long canId = CAN.getCanId();
        //  canHex = 18FFF227;

            Serial.println("-----------------------------");
            Serial.println("get data from ID: ");
           if (canId == 0x18FFF227) {
            Serial.println(canId, HEX);

    // Serial.println(canId);


               mySerial.println("-----------------------------");
            mySerial.println("get data from ID: ");
            mySerial.println(canId,HEX);



//if(buf[0] == 2){

//           for(int i = 0; i<len; i++)    // print the data
//           {
//                Serial.print(buf[i], HEX);
//                       mySerial.print(buf[i], HEX);
//                Serial.print("\t");
//                      mySerial.print("\t");
//            }


//            }  // if 2
//             } // if 1 

          Serial.print(buf[5],HEX);
          Serial.print(buf[4],HEX);
          Serial.print(buf[3],HEX);
          Serial.print(buf[2],HEX);


            Serial.println();
        }
    }

this my current result:

get data from ID:

18FFF227

003cf0

This is what I need:

get data from ID:

18FFF227 15600