Compilare: main.cpp: In function 'int main()': main.cpp:83:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<sf[i].size();j++){ ~^~~~~~~~~~~~~ main.cpp:52:32: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread (buff,1,10000000,fin); ^