Compilare: main.cpp: In function 'int main()': main.cpp:35:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < s1.size(); j++) ~~^~~~~~~~~~~ main.cpp:42:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = s1.size(); j < s2.size(); j++) { ~~^~~~~~~~~~~ main.cpp:64:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < s1.size(); j++) ~~^~~~~~~~~~~ main.cpp:71:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < s2.size()-s1.size(); j++) { ~~^~~~~~~~~~~~~~~~~~~~~