Compilare: user.cpp: In function ‘int main()’: user.cpp:151:33: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings] init("alpin.in", "alpin.out"); ^ user.cpp:151:33: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings] user.cpp: In function ‘char read_char()’: user.cpp:61:40: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf_in, 1, buf_size, fin); ^