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# Splite string into varaibles.

Hello all,

How can I splite a string into several variables, for example.

splite "4+7" into 2 integer and 1 string (4, 7 and "+".

Thank you.
0
superleo
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1 Solution

Commented:
you need to define your parsing rules and write the appropriate code.  Scan the string char by char and every time you hit a "type" boundary (which you define) start saving into a new array element.  Types could be

1) pure numeric
2) pure alpha
3) everything else

or it could be more elaborate.  Your question is too vague to give anything more than a generic answer as I have done.

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Author Commented:
Thank you, in fact my object to convert a string (maths formula) into 3 variables. For example, 32+6 into 32, 6, and "+". How can I save them into 2 integer and 1 string by using "type"??
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Commented:
In the specific case you are siting, you could determine "type" by calling isdigit. Read the string character by character. Check the type with isdigit. As long as the type remains the same, add the character to a receiving string. When the type changes you may need to, if the old type was numeric (isdigit returns true) you would need to convert the receiving string into a number. Depending on the exact nature of your input, you may also need to decide how to treat blanks etc. etc. In psuedo code it would look something like:

char op[5];
int n1,n2,lasttype;

set lasttype to isdigit for first character
while characters left
check if "current" character is same type as last
if it is
add "current" character to receiving string
else
if lasttype was string
copy string in receive to op
else
convert string in receive to n1 or n2
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Commented:
Oh, and one more line at the end of the while:

set lasttype to type of "current" character
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Commented:
2 superleo
int atoi( const char *string );  ??
>...by using "type"??
what do you mean?

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Commented:
say you want to convert the string "32+6" (assuming no spaces before and after the plus sign). Suppose this string is stored in a variable strFormula

char oper[2];
int v1,v2;
char *strFormula="32+6";
sscanf(strFormula,"%d%c%d",&v1,&oper[0],&v2);
oper[1]=0;
printf("%d%s%d\n",v1,oper,v2);

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Commented:
assuming that your string has a lot of variations, like
32+2
32+ 2
32 +2
32 + 2
32 +(2)
ets.
I suggest to use either regexec() and regcomp(), or to implement the parser with (f)lex.
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Commented:
Use strtok()
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Commented:
Here is a function that will split a string into separate variables (char **) and return the number of entries.

#include <stdio.h>
#include <string.h>
#include <split.h>

int     split(char * pstrSource, char ** pstrDest,     char * pstrSeps)
{
auto       int            intNumTokens=0;
auto       char     *     pstrToken=NULL;
static     char     *     pstrDefaultSeps="\t,; ";
static     char     *     pstrSepsToUse=NULL;
if (!pstrSource || !pstrDest)
{
return 0;
}

pstrSepsToUse=pstrSeps;
if (!pstrSepsToUse)
{
pstrSepsToUse=pstrDefaultSeps;
}

pstrToken = strtok( pstrSource, pstrSepsToUse );
while( pstrToken != NULL )
{
pstrDest[intNumTokens]=pstrToken;
intNumTokens++;
pstrToken = strtok( NULL, pstrSepsToUse );
}

return     intNumTokens;
}
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Commented:
0

Commented:
use this but split on space

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

char string[] = "MyXStringXThatXIXWillXSplit";

char **split_text(char *string,char *token, int *count)
{
char **retval = NULL;
char *ptr = NULL;
*count = 0;
ptr = strtok(string,token);
while(ptr != NULL)
{
*count = *count + 1;
retval = (char**)realloc(retval,(*count * sizeof(char*)));
retval[*count - 1] = strdup(ptr);
ptr = strtok(NULL,token);
}
return retval;
}

void main( void )
{
int count = 0;
char **tokens = split_text(string,"X",&count);
for(int i=0;i<count;i++)
{
printf("%i ] %s\n",i,tokens[i]);
}
}
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Commented:
the disadvantage of strtok is that you do not get the matched (tokenized) character, it's just replaced by \0
Not a problem as long as you just have "+" ;-)
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