×
Namespaces

Variants
Actions
(Difference between revisions)

Archived:Converting C strings to numbers

From Nokia Developer Wiki
Jump to: navigation, search
hamishwillee (Talk | contribs)
m (Hamishwillee - Bot fixing redirect link.(Moving links from forum.nokia.com TO developer.nokia.com))
hamishwillee (Talk | contribs)
m (Hamishwillee - Bot change of template (Template:CodeSnippet) - now using Template:ArticleMetaData)
Line 2: Line 2:
 
__NOEDITSECTION__
 
__NOEDITSECTION__
 
{{KBCS}}
 
{{KBCS}}
{{CodeSnippet
+
{{ArticleMetaData
 
|id=CS000891
 
|id=CS000891
 
|platform=S60 3rd Edition
 
|platform=S60 3rd Edition
Line 10: Line 10:
 
|creationdate=April 9, 2008
 
|creationdate=April 9, 2008
 
|keywords=atoi(), atof(), atol(), strtod(), strtol()
 
|keywords=atoi(), atof(), atol(), strtod(), strtol()
 +
 +
|sourcecode= <!-- Link to example source code (e.g. [[Media:The Code Example ZIP.zip]]) -->
 +
|installfile= <!-- Link to installation file (e.g. [[Media:The Installation File.sis]]) -->
 +
|sdk=<!-- SDK(s) built and tested against (e.g. [http://linktosdkdownload/ Nokia Qt SDK 1.1]) -->
 +
|devicecompatability=<!-- Compatible devices (e.g.: All* (must have GPS) ) -->
 +
|signing=<!-- Empty or one of Self-Signed, DevCert, Manufacturer -->
 +
|capabilities=<!-- Capabilities required (e.g. Location, NetworkServices. -->)
 +
|author=[[User:Nymanaki]]
 
}}
 
}}
  

Revision as of 11:21, 24 June 2011


Template:KBCS

Article Metadata
Tested with
Devices(s): Nokia N93
Compatibility
Platform(s): S60 3rd Edition
S60 3rd Edition (initial release)
Platform Security
Capabilities: )
Article
Keywords: atoi(), atof(), atol(), strtod(), strtol()
Created: nymanaki (09 Apr 2008)
Last edited: hamishwillee (24 Jun 2011)

Overview

The simplest way to convert a string to an integer in Open C is to use atoi(). However, atoi() does not differentiate between '0' and invalid input and it does not allow specifying which base you are working with. Other analogous functions to atoi() are atof() and atol(). These functions can be used with the variable types "double" and "long".

Functions strtod() and strtol() offer more control over the conversion process and they will not produce unexpected results on overflow during conversion. These functions make the position of the first unread character in the input string available by assigning it to the second parameter. The function strtol() has also a third parameter to indicate the base of the numeral string.

Note: In order to use this code, you need to install Open C plug-in.

This snippet can be self-signed.

MMP file

The following libraries are required:

LIBRARY  libc.lib

Source file

#include <stdlib.h> //atoi, atof(), atol(), strtod(), strtol()
#include <stdio.h> //printf
 
int main(void)
{
char* int_str = "123"; /* NOTE: atoi will convert e.g. value "xyz" to '0' */
char* double_str = "123.0";
char* long_str = "123456";
 
int int_result = 0;
double double_result = 0.0;
long long_result = 0;
 
char* string_to_convert = NULL;
char* rest_of_the_string = NULL;
double double_value = 0.0;
long long_value = 0;
 
/* functions atoi(), atof() and atol() */
int_result = atoi(int_str);
printf("The string %s as an integer is = %d\n",int_str,int_result);
 
double_result = atof(double_str);
printf("The string %s as a double is = %f\n",double_str,double_result);
 
long_result = atol(long_str);
printf("The string %s as a long is = %ld\n",long_str,long_result);
 
 
/* functions strtod() and strtol() */
string_to_convert = "123.456RestOfTheString";
double_value = strtod(string_to_convert, &rest_of_the_string);
printf("The string = %s, number = %f, rest = %s\n",
string_to_convert, double_value, rest_of_the_string);
 
string_to_convert = "123456789NoMoreNumbers";
rest_of_the_string = NULL;
long_value = strtol(string_to_convert, &rest_of_the_string, 10 ); /* use base 10 */
printf("The string = %s, number = %ld, rest = %s\n",
string_to_convert, long_value, rest_of_the_string);
 
return 0;
}

Postconditions

Five different string-to-number conversions have been executed and are displayed as standard output.

84 page views in the last 30 days.

Was this page helpful?

Your feedback about this content is important. Let us know what you think.

 

Thank you!

We appreciate your feedback.

×