Use union to convert long to bytes

// reference: https://forum.arduino.cc/t/solved-splitting-and-rebuilding-of-long-data-type-numbers/606975/3

//..\Union Example\union_example.ino

// doesn't work on Leonardo but could work on Nano 

//

typedef union u_conv

{

    long    lValue;

    byte    lByte[4];

};

u_conv

    strt,

    finish;

     

void setup() 

{

    Serial.begin(9600);

    strt.lValue = 2147483643;

    Serial.println("Original values:");

    Serial.println(strt.lValue, DEC);

    Serial.println(strt.lValue, BIN);

    //send start.lByte[0..3] to storage medium

    //

    //here, the retrieval is simulated by copying the byte values from the "strt" union

    //to the corresponding byet values in the "finish" union

    //

    //in use, you'd retrieve the bytes from storage and put them in a destination union

    for( int i=0; i<4; i++ )

        finish.lByte[i] = strt.lByte[i];

    Serial.println("Processed values:");

    Serial.println(finish.lValue, DEC);

    Serial.println(finish.lValue, BIN);

}//setup

void loop() 

{

}//loop