CODEWITHSUNDEEP
cstrtok
José Cunha
José Cunha

Reputation: 107

Strtok() not splitting the array properly

I was trying to split the array I received as an argument in a function using strtok() and it simply don't work as expected. For example I receive this string : "ls -l" and I got only "ls". Furthermore , I want to store the tokens into an array of strings. Here is what I have done so far:

int mysystem(char *s) {
    int i;
    char *tok , *aux;
    int conta = 0;
    int pid, status;
    int j = 0;

    tok = strtok(s , " ");

    while (tok != NULL) {
        tok = strtok(NULL, s);
        conta++;
    }

    char *store[conta];
    i = 0;
    aux = strtok(s ," ");

    while (aux != NULL) {
        store[i] = aux;
        aux = strtok(NULL, s);
        i++;
    }

    pid = fork();
    if (pid == 0)
        execvp(store[0], store);

    while (j != conta) {
        wait (&status);
        j++;
    }
    return 0;
}

This is the main of where I'm passing the string to my function :

int main(int args, char **arg) {
    int i;
    int s;
    int f = 0;

    if (args >= 2) {
        int length = 0;

        for (i = 1; i < args; ++i) {
            length += strlen(arg[i]);
        }
        char *output = (char*)malloc(length + 1);
        char *dest = output;
        i = 1;

        while (i < args) {
            dest = strcat (dest,arg[i]);
            i++;
            if (i < args) {
                dest = strcat (dest," ");
            } 
        }       
        dest = strcat(dest, "\0");
        s = mysystem(dest);
        free(output);
        return s;
    }
}

Upvotes: 0

Views: 182

Answers (1)

stark
stark

Reputation: 13189

strtok modifies the string, so you can't run it twice on the same string. s has been converted to a series of strings separated by NUL characters. Change to using an array which is "long enough" and just go through s once.

Upvotes: 1

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