Int values to HEX ?

Projects Networking, Protocols, and Devices
1

Hi guys i'm trying to use two int values and make a long Hex value i have sensorValue0 = 255 & sensorValue1 = 50 what i need is to add them both together in hex like this ( FF32 )
with the following code i get

// = 63ce this one is just 25550 in hex
// = 25550 this one is on the right track but not in HEX ( FF32 )

How can i get this to work then store the value ( FF32 ) for later use?

String string1;
#include <string.h>
char res[5];

int sensorValue0 = 255; // = FF HEX
int sensorValue1 = 50; // = 32 HEX

void setup() {
 Serial.begin(19200);
 String string1 = String ();
 Serial.println("on");
}

void loop() {
  
  sprintf(&res[0], "%04x", sensorValue0*100 + sensorValue1);
  Serial.println(res); // = 63ce
  
  string1 =  String(sensorValue0*100 + sensorValue1); 
  Serial.println(string1); // = 25550

  while(true);
}

:o :o :o :o :o :o :o :o :o :o :o :o

2 
  sprintf(&res[0], "%04x", sensorValue0*100 + sensorValue1);

They are HEX values. The multiplier is 256, not 100.

3

thanks Paul it now gives me ff32 now how can i use ff32 convert into 65330 DEC

void loop() {

sprintf(&res[0], "%04x", sensorValue0*256 + sensorValue1);
Serial.println(res); // = ff32 HEX

tt = res ; // ?

Serial.println(tt); // ff32 HEX = 65330 DEC

while(true);
}

4

I tryed this but the output is

ff32
0

not

ff32
65330

char res[5];
int sensorValue0 = 255; // = FF HEX
int sensorValue1 = 50; // = 32 HEX
int tt = 0;
void setup() {
 Serial.begin(19200);
 String string1 = String ();
 Serial.println("on");
}

void loop() {
  
  sprintf(&res[0], "%04x", sensorValue0*256 + sensorValue1);
  Serial.println(res); // = ff32 HEX

  int tt = atoi(&res[5]);
  Serial.println(tt); // ff32 HEX = 65330 DEC

  while(true);
}
5 
 String string1 = String ();

Create a useless instance of the String class that immediately goes out of scope. Why?

If 0xFF32 is really 65330, how realistic is your expectation that that will fit in an int?

6

how can i convert ff32 and store the value 65330, ? if int cant handle that length of numbers ?

7

Well, long can.

8

You don't want atoi, but rather strtol. Convert string (base 16) to long integer
http://www.cplusplus.com/reference/cstdlib/strtol/

You don't need to go through a hex string conversion when you can just bit shift and combine the two integers into a long.

void setup()
{
  Serial.begin(9600);
  int sensorValue0 = 255; // = FF HEX
  int sensorValue1 = 50; // = 32 HEX
  
  char hex_string[5];
  sprintf(hex_string, "%04x", sensorValue0 * 256 + sensorValue1);
  
  Serial.println(hex_string);
  long val = strtol(hex_string, NULL, 16);
  Serial.println(val);
  
  Serial.println("bitCombineValue");
  long bitCombineValue = ((long)sensorValue0 << 8) | (long)sensorValue1;
  Serial.println(bitCombineValue);

}
void loop()
{
}
9

You don't want atoi, but rather strtol.

It's really pointless to convert two bytes to a string, and then convert the string to a long.

long val = sensorValue0 * 256 + sensorValue1;
10

It's really pointless to convert two bytes to a string, and then convert the string to a long.

Agreed

11 
long val = sensorValue0 * 256 + sensorValue1;

sensorValue0 *256 goes out of range

long val = (long)sensorValue0 * 256 + sensorValue1;