UNIX Power Tools

UNIX Power ToolsSearch this book
Previous: 49.2 bc: Hexadecimal or Binary Conversion Chapter 49
Working with Numbers
Next: 49.4 bc's Sine and Cosine Are in Radians
 

49.3 Gotchas in Base Conversion

Say you want to convert between octal and hex, and you type:

% 

bc
ibase=8
obase=16
17


11

It looks like something's gone haywire. 17 octal ought to be F hexadecimal, not 11. What's wrong?

In fact, since you set ibase to octal before you set obase , what you really asked for was obase equal to 16 octal (14 decimal)!

In short, always set obase before ibase , or you're in for a surprise.

Similarly, suppose you'd set ibase to 16, and want to set it back to 10. You need to type:

ibase=A

not:

ibase=10

Another thing to look out for is typing a hex digit when ibase is set to something other than 16. bc isn't smart enough to reject the input, and gives you back garbage.

- TOR


Previous: 49.2 bc: Hexadecimal or Binary Conversion UNIX Power Tools Next: 49.4 bc's Sine and Cosine Are in Radians
49.2 bc: Hexadecimal or Binary Conversion Book Index 49.4 bc's Sine and Cosine Are in Radians

The UNIX CD Bookshelf Navigation The UNIX CD BookshelfUNIX Power ToolsUNIX in a NutshellLearning the vi Editorsed & awkLearning the Korn ShellLearning the UNIX Operating System