Compilare: user.cpp: In function ‘int e_litera(char)’: user.cpp:10:18: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if ('a' <= t && t <= 'z' || 'A' <= t && t <= 'Z') return true; ^ user.cpp: In function ‘int main()’: user.cpp:15:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("text.in", "r", stdin); ^ user.cpp:16:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("text.out", "w", stdout); ^