Compilare: main.cpp: In function 'void apm(int)': main.cpp:42:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v.size();i++){ ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:73:41: warning: unused variable 'c' [-Wunused-variable] int a = mch[i].a, b = mch[i].b, c = mch[i].c; ^