Compilare: main.cpp: In function 'int main()': main.cpp:19:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<s1.size();i++){ ~^~~~~~~~~~ main.cpp:22:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s1.size();i++){ ~^~~~~~~~~~ main.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s1.size();i++){ ~^~~~~~~~~~ main.cpp:32:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=s1.size();i<s2.size();i++){ ~^~~~~~~~~~