Compilare: main.cpp: In function 'int main()': main.cpp:18:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < s.size(); i ++) ~~^~~~~~~~~~ main.cpp:37:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j <s.size(); j ++) ~~^~~~~~~~~ main.cpp:15:9: warning: unused variable 'n' [-Wunused-variable] int n, m, poz = 0, poz2 = 0, x; ^