Compilare: main.cpp: In function 'int main()': main.cpp:102:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 2; k < s.size(); k++) ~~^~~~~~~~~~ main.cpp: In function 'void read_buffer()': main.cpp:19:50: 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); ^