Compilare: main.cpp: In function 'int main()': main.cpp:16:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < strlen(S) ; i++) ~~^~~~~~~~~~~ main.cpp:18:24: warning: suggest parentheses around '&&' within '||' [-Wparentheses] if(S[i] >= 'a' && S[i] <= 'z' || S[i] >= 'A' && S[i] <= 'Z') nrC++; ~~~~~~~~~~~~^~~~~~~~~~~~~~