Compilare: user.cpp: In function ‘void add()’: user.cpp:23:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<st.size(); i++) ^ user.cpp: In function ‘void solve()’: user.cpp:34:25: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if('a'<=text[i] && text[i]<='z' || 'A'<=text[i] && text[i]<='Z' || '0'<=text[i] && text[i]<='9') ^ user.cpp:34:89: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if('a'<=text[i] && text[i]<='z' || 'A'<=text[i] && text[i]<='Z' || '0'<=text[i] && text[i]<='9') ^ user.cpp: In function ‘int main()’: user.cpp:59:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<afisare.size(); i++) ^ user.cpp:53:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.in","r",stdin); ^ user.cpp:54:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.out","w",stdout); ^