Compilare: main.cpp: In function 'int main()': main.cpp:66:35: warning: array subscript has type 'char' [-Wchar-subscripts] while(k1>0&&pr[st1[k1]]>=pr[s[i]]) ^ main.cpp:66:45: warning: array subscript has type 'char' [-Wchar-subscripts] while(k1>0&&pr[st1[k1]]>=pr[s[i]]) ^ main.cpp: In function 'long long int op(char, long long int, long long int)': main.cpp:29:1: warning: control reaches end of non-void function [-Wreturn-type] } ^