Compilare: user.c: In function ‘main’: user.c:124:4: warning: passing argument 1 of ‘fprintf’ from incompatible pointer type [enabled by default] fprintf( "-1", fout ); ^ In file included from /usr/include/stdio.h:934:0, from user.c:1: /usr/include/i386-linux-gnu/bits/stdio2.h:96:1: note: expected ‘struct FILE * restrict’ but argument is of type ‘char *’ fprintf (FILE *__restrict __stream, __const char *__restrict __fmt, ...) ^ user.c:124:4: warning: passing argument 2 of ‘fprintf’ from incompatible pointer type [enabled by default] fprintf( "-1", fout ); ^ In file included from /usr/include/stdio.h:934:0, from user.c:1: /usr/include/i386-linux-gnu/bits/stdio2.h:96:1: note: expected ‘const char * restrict’ but argument is of type ‘struct FILE *’ fprintf (FILE *__restrict __stream, __const char *__restrict __fmt, ...) ^ user.c:94:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d%d\n", &n, &m ); ^