Compilare: user.cpp: In function ‘int main()’: user.cpp:133:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[i].size();j++){ ^ user.cpp:143:25: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long long int’ [-Wformat=] fprintf(fo,"%d", sum); ^ user.cpp: In function ‘char nextch()’: user.cpp:11:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, fi); ^