Compilare: main.cpp: In function 'mult eval(int, int)': main.cpp:151:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp: In function 'void get_paranthesis()': main.cpp:163:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < s.size();) ~~^~~~~~~~~~ main.cpp: In function 'void output(mult)': main.cpp:188:6: warning: unused variable 'i' [-Wunused-variable] {int i; ^ main.cpp: In function 'void initialise(std::__cxx11::string)': main.cpp:197:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 2; i < x.size();) ~~^~~~~~~~~~ main.cpp:224:33: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized] for (i = start; i <= End; i += r) { ~~^~~~ main.cpp:224:23: warning: 'End' may be used uninitialized in this function [-Wmaybe-uninitialized] for (i = start; i <= End; i += r) { ~~^~~~~~ main.cpp:224:33: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized] for (i = start; i <= End; i += r) { ~~^~~~