#include
     
      //字符串hashaunsigned int hasha(char * url, int mod){    unsigned int n = 0;    char * b = (char*) &n;    for(int i = 0; url[i]; i++)        b[i % 4] ^= url[i];        return n % mod;} int main(){    char str[] = "Hello World\n";    //char *str = "Hello World\n";是错误的    //原因：hello world 应该被分配到了常量区中，而声明的str指针在栈里    //而char str[] = "Hello World\n"; 字符串在栈中。    printf("%d", hasha(str, 25013));}