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Top Forums Programming C: inputting string of unknown length Post 303040993 by DevuanFan on Monday 11th of November 2019 08:58:45 PM
Old 11-11-2019
Andrew, thank you so much for your beautiful explanation. I understand the issue and can confirm that this works exactly as expected:

Code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define SIZE 4

int main(void)
{
	int mem = SIZE;
	char *str = malloc(mem); // let's keep str pointing to beginning of string...
	char *next_read = str; // ...and next_read pointing to where next character should go

	fgets(next_read, mem, stdin);
	printf("str is now %s\n", str);

	while(str[strlen(str)-1] != '\n') // if we got whole string, the last char will be '\n'
	{
		mem += SIZE;
		str = realloc(str, mem); 
		next_read = str + strlen(str);
		fgets(next_read, SIZE+1, stdin); // read the rest (hopefully) of the line into the new space
		printf("str is now %s\n", str);
	}

	printf("final str is %s", str);
	// free(str);
	return 0;
}

Code:
bruno@thinkpad:~/Desktop444$ gcc getstring.c
bruno@thinkpad:~/Desktop445$ ./a.out 
I love linux and the C programming language
str is now I l
str is now I love 
str is now I love linu
str is now I love linux an
str is now I love linux and th
str is now I love linux and the C 
str is now I love linux and the C prog
str is now I love linux and the C programm
str is now I love linux and the C programming 
str is now I love linux and the C programming lang
str is now I love linux and the C programming language
str is now I love linux and the C programming language

final str is I love linux and the C programming language

It is strange that realloc() reallocates in situ at first, then not. Knowing that there are no guarantees was the key to the mystery. THANK YOU Smilie
This User Gave Thanks to DevuanFan For This Post:
 

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METAPHONE(3)								 1							      METAPHONE(3)

metaphone - Calculate the metaphone key of a string

SYNOPSIS
string metaphone (string $str, [int $phonemes]) DESCRIPTION
Calculates the metaphone key of $str. Similar to soundex(3) metaphone creates the same key for similar sounding words. It's more accurate than soundex(3) as it knows the basic rules of English pronunciation. The metaphone generated keys are of variable length. Metaphone was developed by Lawrence Philips <lphilips at verity dot com>. It is described in ["Practical Algorithms for Programmers", Bin- stock & Rex, Addison Wesley, 1995]. PARAMETERS
o $str - The input string. o $phonemes - This parameter restricts the returned metaphone key to $phonemes characters in length. The default value of 0 means no restric- tion. RETURN VALUES
Returns the metaphone key as a string, or FALSE on failure. EXAMPLES
Example #1 metaphone(3) basic example <?php var_dump(metaphone('programming')); var_dump(metaphone('programmer')); ?> The above example will output something similar to: string(7) "PRKRMNK" string(6) "PRKRMR" Example #2 Using the $phonemes parameter <?php var_dump(metaphone('programming', 5)); var_dump(metaphone('programmer', 5)); ?> The above example will output something similar to: string(5) "PRKRM" string(5) "PRKRM" PHP Documentation Group METAPHONE(3)
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