1.利用联合体所有成员起始位置一致

bool isLittleEndian()
{
    union isLittle_Endian
    {
        int i;
        char c;
    };
    isLittle_Endian check;
    check.i = 1;
    return check.c == 1;
}

 O "是小端模式吗? " << isLittleEndian();

1.利用强制类型转换

bool isLittleEndian2()
{
    int val = 0x12345678;
    short *s = (short *)&val;
    return s[1] == 0x1234;
}

 O "是小端模式吗? " << isLittleEndian2();