Question

Actually I need to handle situation like

I should be giving input as rows <n>
There should be space between ‘rows’ and number <n> or any single non numeric character.

I should be able to separate that string part and assign it to a char variable and number part to a int…

The string part should be then verified whether its a correct command or not.. If a wrong command is entered like “ada aad 99” or “adaha 9” or “adfad9”.. It should say “its wrong command”.

I tried to use strtok(), but it can’t handle strings where there isn’t NULL in between strings.. I tried to use $ sscanf(string,"%s %*c %d",str, &num);
but its even not working for all possibilities.

How can I do it?

Answer 1

I don’t see your problem with strtok, it would be perfect in this case I think.

In pseudo-code:

line = getline();
split_line_into_tokens(line);
if tokens[0] == "command1" {
    if tokens_num > 2 {
        error("to many arguments to command1");
    } else if tokens_num < 2 {
        error("command1 needs one argument");
    } else {
        do_command_1(tokens[1]);
    }
} else {
    error("unknown command");
}

In the above pseudo-code, split_line_into_tokens() uses strtok to create an array of tokens, using space as the separator. If strtok returns an empty string (not NULL) then there is more than one space used and you skip that. The split_line_into_tokens creates the tokens array, which first entry contains the command, and the remaining contains the arguments. The variable tokens_num is set to the number of tokens in the array.