#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio> using namespace std;int main(){    typedef int Status[3];    int a[3][3];    for (int i = 0; i < 3; i++) {        for (int j = 0; j < 3; j++) {            a[i][j] = i*3 + j + 1;        }    }        Status &b = a[0];       //1 2 3    Status &c = a[1];       //4 5 6    Status &d = a[2];       //7 8 9    //test memcmp  比较 b, c元素 1.b > c: 1 , 2.b == c: 0, 3.b < c: -1    cout << memcmp(b, c, sizeof(c)) << endl;    //test memcpy, 将 c数组元素都拷贝到d中     memcpy(&d, &c, sizeof(c));    for (int i = 0; i < 3; i++) {        cout << d[i] << " ";            }
    for (int i = 0; i < 3; i++) {        cout << a[2][i] << " ";        //同时也改变了 a[2]这行数据     }    //这两个函数，完成整块内存的比较和复制, 比循环比较和赋值要快     }