i have a subroutine responsible for writing
some chars to LCD screen,there is no error
in function WR_DATA(),after the subroutine
executed,there are some random characters
on the screen except the strings i expected,
i doubt that the program goes to a place
beyond what i expected,but i don't know how to fix. the following is my program:

void WriteString(char* str)
{

while(str){
WR_DATA(*str);
str++;
};

}


can anyone help me out