I'm unable to understand this example given in manpage of dc: $ dc 1 0:a 0Sa 2 0:a La 0;ap 1 To me answer should be 2 because: 1. 1 0:a Here we store 1 at 0th position of array a. 2. 0Sa Now we push 0 to the stack of register a. 3. 2 0:a Now here again we store 2 at 0th position of array a thereby overwriting the previous 1 stored at that location. 4. La Now we pop the 0 stored on stack of register a and push it to main stack. 5. 0;a Now we again push 0 to the main stack and then pop it to use as an array index and so we push the 2 stored at 0th location of array a to the main stack. 6. p Now we print the top of main stack which is 2. So answer should be 2. What am I missing? PS- I wanted to use dc as a tag but looks like it doesn't exist and it's compulsory to use at least one tag so used debian (my workstation OS).

Is there a way to use exponents with fractional components in dc? Example:

user@box:~$ dc
9k

2 2 ^ p
4

2 2.5 ^ p
Runtime warning: non-zero scale in exponent
4

The man page states:

Arithmetic
...
       ^      Pops two values and exponentiates, using the first value  popped
              as the exponent and the second popped as the base.  The fraction
              part of the exponent is ignored.  The precision value  specifies
              the number of fraction digits in the result.

*The fraction part of the exponent is ignored.* It seems plain, but is there a simple way around this?

Input: > printf 1\n\2\n3\n 1 2 3 Desired output: 0 1 1 Typing printf 1\n\2\n3\n | dc -e '-p' the output is: dc: stack empty dc: stack empty

$ echo "$?" 0 $ echo 'q' | dc || echo "$?" 1 Why is using q to quit dc considered an error? (The test was run on Ubuntu 20.4.)

dc can read command from a file or/and from standard input. If I want to print user input : cat essai_dc [enter a number : ] n ? p dc essai_dc enter a number : 4 4 Now, if I try with a heredoc : dc [enter a number : ] > n > ? > p > EOF enter a number : dc: stack empty I get the same with standard input : cat essai_dc | dc enter a number : dc: stack empty The command ? get the p and execute it but the stack is empty. Is it possible to get it to work (tell dc to wait for the input)

I've been given some challenge: there is an application that provides me some postfix expression and expects to get a solution within 5 seconds. If there is no solution, it quits, otherwise, it provides additional expression. The interface is like follow: etc. If there was only single expression I've thought to use tail -1 command to get the last line to get the expression and use the dc command to evaluate it. However, as there are unknown number of expressions (so far), I can't use it and have to do some loop till the string which is read is not starting with a number (i.e expression). Therefore I've though to use 2 scripts: 1. start the application always send text output to file1 and execute it in the background (script 1) 2. read the last row of a script the file1 (script 2), evaluate a solution and sent it to file2 (script 2) 3. read solution from file2, delete file2 (for next solutions), bring the application to foreground, send a solution and then send the application to background (script 1) However, it seems to be little bit complicate for me. Any suggestions how to simplify the procedure to solve it?

I want to use dc to handle some base 16 numbers with hexadecimal points but I'm running into precision problems. For example, below I'm multiplying F423F.FD by 100, both hex. The expected answer is F423FFD, instead it is giving F423FFA.E1, close but not accurate enough even after rounding. $ dc 16 d i o F423F.FD 100 * p F423FFA.E1 I read that dc was an unlimited precision calculator, and this is not a large number by any means. Is there something I'm doing wrong? Thank for your answers. Given the issues with dc, I bit the bullet and wrote my own parser for real numbers in other bases. If anyone is interested in the code, I can post it here.

When running the dc utility, if I input a very large number, say: 999999999999999999999999999999999999999999999999999999999999999999999999 When I print it out using p, I get: 999999999999999999999999999999999999999999999999999999999999999999999\ 999 Why does it split the output after 69 digits?

I'd like to handle user input in dc. For ?, info dc indicates: '?' Reads a line from the terminal and executes it. This command allows a macro to request input from the user. However, if I type this command sequence to square a number, followed by my input 9: ?d*p 9 I get: dc: stack empty dc: stack empty dc: stack empty Am I misinterpreting what ? does?

When some invalid or undefined commands are executed in dc, it usually just prints a warning. Example: cp dc: stack empty This is nice most of the time, however, there are cases where this is annoying as the desired action actually works. Consider this example: 5 6+sИlИp dc: 0230 unimplemented dc: 0230 unimplemented 11 See? Even if I try to use another register than those in the manual it still works. ("officially" 256, but how are you even supposed to use the NUL byte?) Even if perhaps not always a good idea, I would like dc to now show me such warnings in some scripts. How can I make dc not print warnings?