Compilare: user.cpp: In function ‘void computepre()’: user.cpp:18:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < s1.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:42:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = initsize + 1; i < s1.size(); i++){ ^ user.cpp:51:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < sol.size(); i++) { ^