Strtok use method and principle in C language, and function of self-realization function

#include <stdio.h>

The key point of the program is to define a static character pointer, which is used to record the first address of the split string.

Passing in null means that the remaining string pointed to by the static pointer continues to be processed

Char *strtok (char *str, const char *delim)

{

Static Char *rembmberlaststring=null;//Note the position of the last non-delimited string character, as shown in the illustration

const char *indexdelim=delim;//make a backup of Delim

int flag=1,index=0;//Each call to the Strtok,flag tag will cause the program to record only the first non-delimiter position, and subsequent non-delimiters are no longer processed

Char *temp=null;//return value of the program

if (str==null)

{

str=rembmberlaststring;//If STR is NULL indicates that the program continues to process the last remaining string

}

for (; *str;str++)

{

Delim=indexdelim;

for (; *delim;delim++)

{

if (*str==*delim)

{

*str=null;//If you find a character that is interesting in Delim, set the character to NULL

index=1;//used to mark characters of interest that have occurred

Break

}

}

if (*str!=null&&flag==1)

{

temp=str;//only the position of the current first non-interested character is recorded

flag=0;

}

if (*str!=null&&flag==0&&index==1)

{

rembmberlaststring=str;//the second occurrence of a non-interested character (the character of interest must have occurred before)

return temp;

}

}

rembmberlaststring=str;//executes the sentence to indicate that the character of interest has not been present, or that there is no longer a non-interest character after a character that is of interest

return temp;

}

int main (void)

{

Char strtocken[] = "A string\tof, Tokens\nand some more tokens";

Char strdelimiter[] = ", \t\n";

char * p;

p = Strtocken;

while (P=strtok (P,strdelimiter))

{

printf ("%s\n", p);

p = NULL;

}

return 0;

}

The ability to express is not very good, the technology is limited, but the general meaning is these, hope light spray

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Strtok use method and principle in C language, and function of self-realization function