[c++] string into int? - Tilted Forum Project Discussion Community

j0hnb · 09-12-2004, 01:36 PM

Here is my delema, I scaned in a full line using getline, it would scan in something like 10:45 Pm, how can I take the 10 and put it into an int and then take the 45 and put it into another int? Thanks.

kel · 09-12-2004, 01:43 PM

There is a function called printf or sprintf that can help you convert strings to in. Google "String to int" or "Convert string to int".

Google is a programmers second best friend, second only to java...

Pragma · 09-12-2004, 03:45 PM

The function atoi() turns a char* into an integer, with certain constraints.

There can be whitespace in front of the integer, but no alphabet characters. The number stops when a non-integer character is read.

Valid strings to pass to atoi():
" 103a39" -> 103
"9438745" -> 9438745
"-394" -> -394

Invalid strings:
"a5445a"
".25465"

bacon · 09-12-2004, 05:56 PM

Something else you might want to consider, parsing out "10:45 pm" as a string and using strptime() to convert it to a time structure.

j0hnb · 09-13-2004, 04:36 AM

I didn't even know there was a time structure, i'll try it out, thanks

roboshark · 09-13-2004, 05:01 AM

Use strtol().

(Error and sanity checks omitted)

Code:

char *ptr = "10:45pm";
char *endptr;
int hours, min;

hours = strtol(ptr, &endptr, 0);
/* endptr now set to ":45pm" */
if (endptr == NULL  || *endptr != ':')
       report_error("time format");
endptr++;
ptr = endptr;

min = strtol(ptr, &endptr, 0);

/* endptr now set to "pm" */

ketamine · 09-13-2004, 10:24 AM

You could also use a stringstream:

Code:

#include <sstream>

// ...
// input = "10:45 pm"
std::stringstream buffer(input);
int iHours, iMinutes;
char c;
buffer >> iHours >> c >> iMinutes;

a-j · 09-14-2004, 04:48 PM

I think what you want is sscanf, which does the "opposite" what printf does
Something along the lines of (untested):

sscanf(string, "%i:%i", &hour, &min);

MXL · 09-16-2004, 01:49 PM

use sscanf, note: sscanf will return the number of tokens scanned.

CString sMyString = "10:45";
if (sscanf (sMyString, "%d:%d", &nHour, &nMinute) != 2)
{
// error
}

09-12-2004, 01:36 PM	#1 (permalink)
j0hnb Crazy Location: Arnold, MD	[c++] string into int? Here is my delema, I scaned in a full line using getline, it would scan in something like 10:45 Pm, how can I take the 10 and put it into an int and then take the 45 and put it into another int? Thanks.

09-12-2004, 01:43 PM	#2 (permalink)
kel WARNING: FLAMMABLE Location: Ask Acetylene	There is a function called printf or sprintf that can help you convert strings to in. Google "String to int" or "Convert string to int". Google is a programmers second best friend, second only to java... __________________ "It better be funny"

09-13-2004, 10:24 AM	#7 (permalink)
ketamine Upright Location: Boulder, Colorado	You could also use a stringstream: Code: #include <sstream> // ... // input = "10:45 pm" std::stringstream buffer(input); int iHours, iMinutes; char c; buffer >> iHours >> c >> iMinutes; __________________ /K

09-12-2004, 03:45 PM	#3 (permalink)
Pragma I am Winter Born Location: Alexandria, VA	The function atoi() turns a char* into an integer, with certain constraints. There can be whitespace in front of the integer, but no alphabet characters. The number stops when a non-integer character is read. Valid strings to pass to atoi(): " 103a39" -> 103 "9438745" -> 9438745 "-394" -> -394 Invalid strings: "a5445a" ".25465"

09-12-2004, 05:56 PM	#4 (permalink)
bacon Upright	Something else you might want to consider, parsing out "10:45 pm" as a string and using strptime() to convert it to a time structure.

09-13-2004, 04:36 AM	#5 (permalink)
j0hnb Crazy Location: Arnold, MD	I didn't even know there was a time structure, i'll try it out, thanks

09-14-2004, 04:48 PM	#8 (permalink)
a-j Tilted	I think what you want is sscanf, which does the "opposite" what printf does Something along the lines of (untested): sscanf(string, "%i:%i", &hour, &min);

09-16-2004, 01:49 PM	#9 (permalink)
MXL Tilted Location: Maryland	use sscanf, note: sscanf will return the number of tokens scanned. CString sMyString = "10:45"; if (sscanf (sMyString, "%d:%d", &nHour, &nMinute) != 2) { // error }