Compilare: user.cpp: In function ‘int main()’: user.cpp:121:25: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sir [ ++ cate ] = NULL ; ^ user.cpp:151:25: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sir [ ++ cate ] = NULL ; ^ user.cpp:168:15: warning: unused variable ‘p’ [-Wunused-variable] char *p = sir + 1 ; ^ user.cpp: In function ‘int cauta(int, int)’: user.cpp:99:1: warning: control reaches end of non-void function [-Wreturn-type] } ^