LeafLabs Garden » Topic: how do I implement the String class?

LeafLabs Garden » Topic: how do I implement the String class? http://forums.leaflabs.com/topic.php?id=74322 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:17:55 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php jstamour802 on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105393 Sun, 18 May 2014 08:52:16 +0000 jstamour802 105393@http://forums.leaflabs.com/ thanks a ton for your help - I was able to get everything to work. This put me over a major hump in a project I am working on. high five! ventosus on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105384 Mon, 12 May 2014 11:52:14 +0000 ventosus 105384@http://forums.leaflabs.com/ @jstamour802 I put the 'extern "C"' there only to tell you that this is C code and may need adaptations to run in wirish/C++, and obviously you have found out exactly that ;-) So forget about the 'extern "C". IIRC, the right way to include C headers stdlib.h, string.h or stdio.h in C++ is: #include <cstdlib> #include <cstring> #include <cstdio> I have actually tested both ways and they work fine here. But I use the current launchpad GCC instead of the outdated codesourcery GCC... jstamour802 on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105383 Mon, 12 May 2014 10:31:09 +0000 jstamour802 105383@http://forums.leaflabs.com/ I was able to get <stdlib> to work, I had to add it at the top of my includes <stdlib> ... <other includes> Otherwise it didnt work. The program compiles now, but now your first example doesn't work. It returns a blank value instead of the int. It worked for Arduino however. Also, I cant figure out where to put extern 'C' { without causing problems in my program. What exactly needs to be within the braces? Thanks in advance for any help. jstamour802 on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105382 Mon, 12 May 2014 08:26:46 +0000 jstamour802 105382@http://forums.leaflabs.com/ Also If I try to include <stdlib.h> I get: \maple-ide-0.0.12-windowsxp32\hardware\tools\arm\bin\../lib/gcc/arm-none-eabi/4.4.1/../../../../arm-none-eabi/include/stdlib.h:72 stdlib.h:72: error: expected unqualified-id before 'int' jstamour802 on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105381 Mon, 12 May 2014 08:13:14 +0000 jstamour802 105381@http://forums.leaflabs.com/ ventosus - thank you for your answers. I tried the first example on Arduino and it works well. I then tried it on maple but I get 'atoi' not declared. How do I add 'atoi'? I found this from the FAQ: "How can I use atoi()? The CodeSourcery GCC compiler used to compile your programs is configured to link against the newlib C library, and allows the use of any of its headers." This doesn't tell me much...nor how to make it compile in my program. Is there another step I need to use 'atoi'? Also, I dont have 'String.h'. Where does this library come from? ventosus on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105378 Sun, 11 May 2014 16:26:27 +0000 ventosus 105378@http://forums.leaflabs.com/ Or using sscanf... <code> extern "C" { #include <stdio.h> int pwn; sscanf(req, "GET /ajax_inputs&PWM3=%i", &pwn); printf("%i\n", pwn); } </code> ventosus on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105376 Sun, 11 May 2014 13:41:50 +0000 ventosus 105376@http://forums.leaflabs.com/ This should be straight-forward with the C functions 'strstr' and 'atoi'. <code> extern "C" { #include <string.h> #include <stdlib.h> char *req = "GET /ajax_inputs&PWM3=1000&nocache=120749.0530796349"; char *ptr = strstr(req, "PWM3="); if(ptr) { int pwn = atoi(ptr+5); // use pwn } } </code> jstamour802 on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105374 Sun, 11 May 2014 08:57:57 +0000 jstamour802 105374@http://forums.leaflabs.com/ More specifically, I need to retrieve an integer from a string. I'm working on a web server interface that sends the value of a number field in a string like this: "GET /ajax_inputs&PWM3=1000&nocache=120749.0530796349" I need to extract the "1000" from "PWM3=1000" in the string, and use that value to write to a PWM pin. The string library in Arduino (or the standard C string library for that matter) can do it by the substring method, but is there a different way I can do it without the bloat of the string library? jstamour802 on "how do I implement the String class?" http://forums.leaflabs.com/topic.php?id=74322#post-105365 Mon, 05 May 2014 09:04:03 +0000 jstamour802 105365@http://forums.leaflab