CODEWITHSUNDEEP
cstrtok
Rick_Sch
Rick_Sch

Reputation: 456

A Little strtok() Fun

I am not the best with pointers, so maybe you can see what I'm doing wrong.

Let's say that I have an array that was initialized like this: 

char *arrayOfCommands[]={"ls -l", "wc -l"};

My goal is to get an array called char *currentCommand out of this array that looks at a specific cell of arrayOfCommands and separates the command into pieces on spaces.

My final goal would be to have a new currentCommand array on each loop that each look like this:

First Loop:  
currentCommand = [ls][-l]

First Loop:  
currentCommand = [wc][-l]

Here is the code I have so far:

for (i = 0; i < 2; ++i) {
    char str[] = arrayOfCommands[i];
    char * currentCommand;
    printf ("Splitting string \"%s\" into tokens:\n",str);
    currentCommand = strtok (str, " ");
    while (currentCommand != NULL){
        printf ("%s\n",currentCommand);
        currentCommand = strtok (NULL, " ");
    }

    .
    .
    .

    //Use the currentCommand array (and be done with it)
    //Return to top
}

Any help would be greatly appreciated! :)

UPDATE:

for (i = 0; i < commands; ++i) {
    char str[2];
    strncpy(str, arrayOfCommands[i], 2);
    char *currentCommand[10];
    printf ("Splitting string \"%s\" into tokens:\n",str);
    currentCommand = strtok (str, DELIM);
    while (currentCommand != NULL){
        printf ("%s\n",currentCommand);
        currentCommand = strtok (NULL, DELIM);
    }
}

I am getting this error: ** incompatible types in assignment**
It's talking about the "str" I'm passing the strtok function.

Upvotes: 0

Views: 381

Answers (1)

pb2q
pb2q

Reputation: 59617

strtok operates by modifying the string that you pass; this is easy to miss when using some man pages. Each command in your array is a literal string: attempts to modify them will cause problems. So you'll need to make a copy of each command before using it with strtok.

Furthermore, this is an invalid initialization for an array:

char str[] = arrayOfCommands[i];

Declare str as an array of some fixed size, then use strncpy to make copies of each command before tokenizing them using strtok:

char str[MAX_COMMAND_LEN + 1];
strncpy(str, arrayOfCommands[i], MAX_COMMAND_LEN);

// ...

Upvotes: 2

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