Compilare: main.cpp: In function 'int main()': main.cpp:13:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(s);i++) ~^~~~~~~~~~ main.cpp:14:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses] if(s[i]>='a' && s[i]<='z' || s[i]>='A' && s[i]<='Z') ~~~~~~~~~~^~~~~~~~~~~~