Compilare: main.cpp: In function 'int main()': main.cpp:67:27: warning: format '%d' expects argument of type 'int', but argument 3 has type 'i64 {aka long long int}' [-Wformat=] fprintf(out, "%d", ret) ; ^ main.cpp:50:27: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d ", &n) ; ^ main.cpp:52:33: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", v + i) ; ^