Compilare: main.cpp: In function 'void multiply(long long int, long long int)': main.cpp:62:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < prime.size(); i++) ~~^~~~~~~~~~~~~~ main.cpp: In function 'void divide(long long int, long long int)': main.cpp:81:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < prime.size(); i++) ~~^~~~~~~~~~~~~~ main.cpp: In function 'long long int get(long long int)': main.cpp:99:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < prime.size(); i++) ~~^~~~~~~~~~~~~~ main.cpp: At global scope: main.cpp:105:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^ main.cpp: In function 'int main()': main.cpp:134:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < prime.size(); i++) ~~^~~~~~~~~~~~~~