程序代码：

void f(char *s)
{
    printf("1:s=%s\n", s);
    char *p = s;
    *(p+1) = 'A';
    printf("2:s=%s s[1]=%c\n", s, s[1]); // 应该输出：1A23456789
}

int main()
{
    int a = 0;     
    char *s  = "123456789";    
    char q[] = "123456789";
    f(s);
    printf("---------------------------------------------------\n");
    f(q);
}