CODEWITHSUNDEEP
cpointerschar
Dezzy
Dezzy

Reputation: 117

First character of pointer

I have a question regarding char pointers.

I am reading a file in C, using fgets. This is a short overview so you can understand what I would like to do:

char configline[configmax_len + 1]; //configmax_len is the max value I need
while(fgets(configline, sizeof(configline), config){ //config is the file
    char *configvalue = strtok(configline, " ");
    if (configvalue[0] == "#"){
        continue;
    }
    …
}

char * configvalue is a pointer to the current line being read. What I would like to check is if the first character of the line is a "#".

However when I do the if statement: if (configvalue[0] == "#"), the compiler throws an error: comparison between pointer and integer.

How could I check if the first character of the string a pointer is pointing to is a certain value?

Upvotes: 4

Views: 12449

Answers (3)

Nunchy
Nunchy

Reputation: 948

Strtok returns a pointer to a nul terminated string, but you're comparing this with a string constant using ==:

if (configvalue[0] == "#")

Firstly, configvalue is a pointer, so you could do something like:

if (*configvalue == '#')

To dereference the pointer and get the first character in the output string.

Upvotes: 1

Tom
Tom

Reputation: 936

try using 

if (configvalue[0] == '#'){

this should compile nicely

Upvotes: 6

Scott Hunter
Scott Hunter

Reputation: 49803

Use single quotes to denote a single character; double quotes denote strings, which are represented by a pointer to the first character, hence the error message.

Upvotes: 6

Related Questions