Compilare: main.cpp:13:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("O3") main.cpp:14:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("unroll-loops") main.cpp: In function 'int read_int()': main.cpp:60:35: warning: array subscript has type 'char' [-Wchar-subscripts] while(!isDigit[c = read_char()]); ^ main.cpp:62:20: warning: array subscript has type 'char' [-Wchar-subscripts] while(isDigit[c]) ^ main.cpp: In function 'char read_char()': main.cpp:33:54: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buffer, sizeof(char), BUFFER_SIZE, fin); ^