Compilare: user.cpp: In function ‘int main()’: user.cpp:22:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1 ; i < strlen(sir); ++i) ~~^~~~~~~~~~~~~ user.cpp:24:6: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if ((sir[i] >= 'A'&&sir[i] <= 'Z') || (sir[i] >= 'a'&&sir[i] <= 'z')) ^