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Split C string into tokens using sscanf

Tags:

c

string

c99

I'm trying to split a string into tokens but somewhat recursively. I am trying to parse:

"content=0&website=Google"

so that I have a way to take out the parameters and values. If I try strtok I end up destroying the string I want to parse twice. So I tried

char *contents = "content=0&website=Google"
char arg[100];
char value[100];
sscanf(contents, "%s&%s", arg, value);

as a first pass, hoping to parse arg again, but it fails, and arg contains the entire string. I tried using "%s\&%s" thinking & was a reserved word, but no luck there.

Help!

Edit:

This was my strtok hack:

static void readParams(char * string, char * param, char * value) {
    printf("This is the string %s\n",string);
    char * splitted = strtok (string,"=");

    while (splitted != NULL)
    {
        printf("This is the string %s\n",splitted);
        splitted = strtok (NULL, "=");
        // Then do some saving to param and value
    }
}
char * splitted = strtok (contents,"&");
int counter = 0;

while (splitted != NULL)
{
    char * t_str = strdup(splitted);
    readParams(t_str, param, value);
    splitted = strtok (NULL, "&");
}

but it doesn't work because splitted's strtok at the end becomes gobbldygook.

like image 855
Rio Avatar asked Jul 28 '26 21:07

Rio


2 Answers

Here is a solution that seems to work:

char *contents = "content=0&website=Google";
char arg[100] = {0};
char value[100] = {0};
sscanf(contents, "%[^&]&%s", arg, value);
printf("%s\n%s\n", arg, value);
like image 60
Donotalo Avatar answered Jul 30 '26 12:07

Donotalo


scanf is more primitive than you seem to think — %s will match everything up to the next whitespace. Your best solution is probably to stick with strtok but throw it only content you've strduped from the authoritative original.

like image 27
Tommy Avatar answered Jul 30 '26 10:07

Tommy



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