Compilare: user.cpp:7:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^ user.cpp: In function ‘int main()’: user.cpp:17:27: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (s[i]<='z' && s[i]>='a' || s[i]<='Z' && s[i]>='A') ^ user.cpp:13:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s,10000,in); ^