分流/解析，并从字符数组获得价值 [英] split/parse and get value from a char array

问题描述

我想用C编写的函数，通过它我可以从一个字符数组：

I want to write a function in C, by which I can get value of the tag from a char array ::

例：

char a[]="name=RRR&school=AAA&roll=111&address=SSS";

我想编写一个函数 - 如果我给名作为函数的参数则函数将返回RRR ---如果我给学校作为函数的参数则函数将返回AAA

I want to write a function - if I give "name" as a parameter of the function then the function will return RRR --- if I give "school" as a parameter of the function then the function will return AAA

我已经在Java中做到了......

i have done it in Java ...

    public String getTagValue(String toSplit, String tag)
{
    String CommandTypeValue="";
    String[] FirstSplit;
    String[] SecondSplit;

    String delims = "&";
    FirstSplit = toSplit.split(delims);

    for(int i=0; i<FirstSplit.length; i++ )
    {
        delims = "=";
        SecondSplit = FirstSplit[i].split(delims);
        if(SecondSplit[0].equals(tag))
            return SecondSplit[1];
        //System.out.println(SecondSplit[0] +" "+ SecondSplit[1]);
    }

    return CommandTypeValue;

}

如何给它C 17没有简单的库或函数??

推荐答案

的strtok 是你所期待的。

例如：

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


char* getTagValue(char* a_tag_list, char* a_tag)
{
    /* 'strtok' modifies the string. */
    char* tag_list_copy = malloc(strlen(a_tag_list) + 1);
    char* result        = 0;
    char* s;

    strcpy(tag_list_copy, a_tag_list);

    s = strtok(tag_list_copy, "&");
    while (s)
    {
        char* equals_sign = strchr(s, '=');
        if (equals_sign)
        {
            *equals_sign = 0;
            if (0 == strcmp(s, a_tag))
            {
                equals_sign++;
                result = malloc(strlen(equals_sign) + 1);
                strcpy(result, equals_sign);
            }
        }
        s = strtok(0, "&");
    }
    free(tag_list_copy);

    return result;
}

int main()
{
    char a[]="name=RRR&school=AAA&roll=111&address=SSS";

    char* name    = getTagValue(a, "name");
    char* school  = getTagValue(a, "school");
    char* roll    = getTagValue(a, "roll");
    char* address = getTagValue(a, "address");
    char* bad     = getTagValue(a, "bad");

    if (name)    printf("%s\n", name);
    if (school)  printf("%s\n", school);
    if (roll)    printf("%s\n", roll);
    if (address) printf("%s\n", address);
    if (bad)     printf("%s\n", bad);

    free(name);
    free(school);
    free(roll);
    free(address);
    free(bad);

    return 0;
}

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