当前位置 博文首页 > 谁吃薄荷糖：【?C/C++の深入浅出?】int数与多枚举值互转
在C/C++在C/C++的开发中经常会遇到各种数据类型互转的情况，正常的互转有：单个枚举转int数，int数转float数，float数转double数等。但是我们有时也会遇到多个枚举值与数字互转的情形（例如多个算法类型枚举开启标志转成数字，这个数字来表示多个标志位，按位来表示）。这样一个数字就能表示很多个标志位了，针对内存较少的嵌入式设备，这么操作可以达到节约内存消耗，提高程序运行效率的目的。
demo核心知识点：通过位运算符（布尔位运算符："~"、"&"、"|"；移位运算符："<<"）实现int数与多枚举值互转。
Code:
#include <iostream>
using namespace std;
int nFlag = 0; //用移位表示各个枚举的开关
typedef enum
{
TYPEA, //A开启，则nflag为1=0x00000001
TYPEB, //B开启，则nflag为2=0x00000010
TYPEC, //C开启，则nflag为4=0x00000100
TYPED, //D开启，则nflag为8=0x00001000
TYPENUM //枚举最大值，计数用
}EMTypeNum;
void int2enum (int n)
{
if(n&(0x01<<TYPEA))
{
//为真
cout << "TYPEA is ON\n";
}
else
{
//为假
cout << "TYPEA is OFF\n";
}
if(n&(0x01<<TYPEB))
{
//为真
cout << "TYPEB is ON\n";
}
else
{
//为假
cout << "TYPEB is OFF\n";
}
if(n&(0x01<<TYPEC))
{
//为真
cout << "TYPEC is ON\n";
}
else
{
//为假
cout << "TYPEC is OFF\n";
}
if(n&(0x01<<TYPED))
{
//为真
cout << "TYPED is ON\n";
}
else
{
//为假
cout << "TYPED is OFF\n";
}
}
void enum2int(EMTypeNum eMType, bool bOn)
{
if(bOn)
{
nFlag |= (0x01 << eMType);
}
else
{
nFlag &= ~(0x01 << eMType);
}
cout << "nFlag:" << nFlag << endl;
}
int main() {
int i = 0;
for(i = 0; i < TYPENUM;i++)
{
enum2int((EMTypeNum)i, true);
int2enum(nFlag);
cout << endl;
}
for(i = 0; i < TYPENUM;i++)
{
enum2int((EMTypeNum)i, false);
int2enum(nFlag);
cout << endl;
}
return 0;
}
Result:
nFlag:1
TYPEA is ON
TYPEB is OFF
TYPEC is OFF
TYPED is OFF
nFlag:3
TYPEA is ON
TYPEB is ON
TYPEC is OFF
TYPED is OFF
nFlag:7
TYPEA is ON
TYPEB is ON
TYPEC is ON
TYPED is OFF
nFlag:15
TYPEA is ON
TYPEB is ON
TYPEC is ON
TYPED is ON
nFlag:14
TYPEA is OFF
TYPEB is ON
TYPEC is ON
TYPED is ON
nFlag:12
TYPEA is OFF
TYPEB is OFF
TYPEC is ON
TYPED is ON
nFlag:8
TYPEA is OFF
TYPEB is OFF
TYPEC is OFF
TYPED is ON
nFlag:0
TYPEA is OFF
TYPEB is OFF
TYPEC is OFF
TYPED is OFF
有关int数与多枚举值互转的介绍就到此结束啦！下篇博文与各位再见面~
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