Compilare: main.cpp: In function 'int main()': main.cpp:55:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < ordered_sol.size(); i++) { ~~^~~~~~~~~~~~~~~~~~~~ main.cpp:56:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < sol[ordered_sol[i]].size(); j++) { ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:25:31: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buf, MAXBUF, 1, fin); ^ main.cpp: In function 'void read(int&)': main.cpp:94:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buf, MAXBUF, 1, fin); ^ main.cpp:105:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buf, MAXBUF, 1, fin); ^