convert HEX (ASCII) to a DEC int

Forum 2005-2010 (read only) Software Syntax & Programs
1

Hi,

I get on Arduino Serial a string like "CC", and I need to convert it to a int with decimal value of 0xCC (that is 204).

I found in the Forum, some topics about convert long-long values (convert a big string with hex value, to a very big decimal value), or simply get the hex representation of the ASCII character (like 'C' = 0x43) and this isn't what I want.

Knows someone a function to do the simple conversion ("CC -> 204)?

2 
hexDigit = toupper(hexDigit);
digit = (hexDigit >= 'A') ? hexDigit - 'A' + 10 : hexDigit - '0';

"toupper", range checking and double digit conversion is left as an exercise for the reader.

3

... or you could leave the exercises for others and use either the strtol() or strtoul() function.

4

Where's the fun in that?

5

Works fine!

I figured it was simple like atoi, atof, atol, but I don't knew exactly what to look for.

Thanks!

6

sscanf() is also an option especially for multiple hex codes in one string.

char s[] = "CC 0D";
int xx; 
int yy;
sscanf(s, "%x %x", &xx, &yy);  
Serial.print(xx);
Serial.print(yy);