HEX string to unsigned long.

Projects Programming
1

Hello all. Little guidance needed on converting a HEX string for example char str[5] contains BE 1F A8 13. Am wanting to add the 4 bytes together and place the answer into a unsigned long. Would a simple for loop work for this with the += compound operator?

Many thanks as always.

2

Would a simple for loop work for this with the += compound operator?

By itself, no it wouldn't.
But some left shifts or some multiplies would sort it out.

Edit:

BE 1F A8 13.

Do you mean you want the sum of those values (0x198) in a 32 bit variable, or the value 0xbe1fa813 in a 32 bit variable?

Do you know the endianess of the input value?
uncompiled untested

unsigned long var = 0;
for int (int i = 0; i < 4; ++i) {
  var <<= 8;
  var+= array [i];
}
3

Do you mean you want the sum of those values (0x198) in a 32 bit variable, or the value 0xbe1fa813 in a 32 bit variable?

Hello mate, yes i want the sum 198 hex, 408 DEC to go into a 32 bit variable.

4

In which case the same loop without the shift.
You'll also need to cast the "char" to "unsigned char"

You'll also have at most ten bits of data in a 32 bit variable.

5

I notice you use use
var <<= 8;
does this mean the unsigned long variable fills from right to left?

Sorry just noticed your last post lol.