Compilare: user.cpp: In function ‘int main()’: user.cpp:12:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf( f, "%d\n", &N ); ^ user.cpp:13:37: warning: ignoring return value of ‘size_t fread_unlocked(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread_unlocked( c, 1, MAX_N, f ); ^ user.cpp:15:21: warning: ‘i’ is used uninitialized in this function [-Wuninitialized] s[ 0 ] = ( c[ i ] == 48 ) ? -1 : 1; ^