How to use parse function in c language

The parse function parses a string, converting it into a list of tokens separated by a delimiter. Steps: 1. Search for the first non-delimiter character from the beginning of the string; 2. Continue searching until a delimiter is encountered and terminate the string at that delimiter; 3. Store the token in the token array; 4 . Repeat steps 1-3 until the end of the string; 5. Add a pointer to NULL at the end of the array to indicate the end of the array.

Usage of parse function in C language

parse function is a C language function that parses a string into a sequence of tokens. Tokens are words, phrases, or other units in a string that are separated by spaces or other delimiters.

Usage:

parse The syntax of the function is as follows:

<code class="c">char **parse(char *s, char *d);</code>

Among them:

• s: The string to be parsed.
• d: A delimiter string used to parse strings into tokens.

Return value:

parse The function returns a pointer to the token array, each element in the array is a A string to store the token. If parsing succeeds, a pointer to the first token is returned; if parsing fails, NULL is returned.

Detailed description:

parse The function parses the string through the following steps:

1. Start from the beginning of the string , searches for the first character that is not part of the delimiter string.
2. Treat this character as the beginning of the token and continue searching until the delimiter is encountered.
3. At the delimiter, terminate the string (add a null character) and store the token in the token array.
4. Repeat steps 1-3 until there are no more characters in the string.
5. Add a pointer to NULL at the end of the token array to indicate the end of the array.

Example:

The following code demonstrates how to use the parse function to parse a string into words:

<code class="c">#include <stdio.h>
#include <stdlib.h>

int main() {
    char *s = "Hello, world!";
    char *d = " ,";

    char **tokens = parse(s, d);

    if (tokens) {
        int i = 0;
        while (tokens[i]) {
            printf("%s\n", tokens[i]);
            i++;
        }
        free(tokens);  // 释放令牌数组
    }

    return 0;
}</code>

Running this code will output the following results:

<code>Hello
world</code>

The above is the detailed content of How to use parse function in c language. For more information, please follow other related articles on the PHP Chinese website!