Compilare: main.cpp: In function 'void multiply(long long int)': main.cpp:64:19: 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)': main.cpp:82:19: 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()': main.cpp:100:19: 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:106:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^ main.cpp: In function 'int main()': main.cpp:135:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < prime.size(); i++) ~~^~~~~~~~~~~~~~