Thread: Reading a string of given size and printing it back

Hello.

I'm playing around with C and strings.

This is piece of code inside main function:

Code:

char *format;
fscanf(fstream, "%2s", format);


fprintf(stdout, "%s\n", &format);

This is what compiler (gcc) spits out when fprintf uses '&' annotation before string variable:

Code:

string_test.c: In function ‘main’:
string_test.c:23:5: error: format ‘%s’ expects argument of type ‘char *’, but argument 3 has type ‘char **’ [-Werror=format=]
     fprintf(stdout, "%s\n", &format);
     ^
cc1: all warnings being treated as errors

And this is what compiler spits out when fprintf ommits the '&':

Code:

string_test.c: In function ‘main’:
string_test.c:21:11: error: ‘format’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
     fscanf(fstream, "%2s", format);
           ^
cc1: all warnings being treated as errors

What am I supposed to write there then?

Code:

char *format;

"format" is an uninitialized pointer. You have not allocated any memory to put the data into!

Try:

Code:

char format[80];

The print statement should be:

Code:

fprintf(stdout, "%s\n", format);

If you are going to show us error messages from a compile, then you should provide a small complete program that demonstrates the error, that we can compile and test ourselves.