CODEWITHSUNDEEP
cpointersc-strings
NVI
NVI

Reputation: 15045

Slice a beginning of a string in C

void slice_first_char(char ** string)
{
    *string = &(*string[1]);
}

int main(int argc, char * argv[])
{
    char * input = "abc";
    input = &(input[1]);
    puts(input); // "bc" as expected.

    slice_first_char(&input);
    puts(input); // \372\277_\377
                 // What‘s going on?
}

How can I rewrite a slice_first_char function to make it work as expected?

Upvotes: 0

Views: 2224

Answers (2)

singpolyma
singpolyma

Reputation: 11241

You seem to be attempting to remove the first char from a string. So:

char* remove_first_char(const char* s) {
  return (s+1);
}

Upvotes: 3

Frerich Raabe
Frerich Raabe

Reputation: 94349

You got the parentheses in

&(*string[1]);

wrong. I guess you meant

&((*string)[1]);

Your original version dereferences the pointer of the first element of the strings array, and then takes the address of that whereas you actually want to dereference the given pointer (because it just points to a single string), then take the first element of that (the first character) and then take the address of that.

A slighty less convulated way to express this would be

*string + 1

by the way.

Upvotes: 11

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