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C/C++ int數(shù)與多枚舉值互轉(zhuǎn)的實(shí)現(xiàn)

更新時(shí)間：2021年08月25日 09:58:01 作者：誰吃薄荷糖

在C/C++在C/C++的開發(fā)中經(jīng)常會(huì)遇到各種數(shù)據(jù)類型互轉(zhuǎn)的情況，本文主要介紹了C/C++ int數(shù)與多枚舉值互轉(zhuǎn)的實(shí)現(xiàn)，具有一定的參考價(jià)值，感興趣的可以了解一下

在C/C++在C/C++的開發(fā)中經(jīng)常會(huì)遇到各種數(shù)據(jù)類型互轉(zhuǎn)的情況，正常的互轉(zhuǎn)有：單個(gè)枚舉轉(zhuǎn)int數(shù)，int數(shù)轉(zhuǎn)float數(shù)，float數(shù)轉(zhuǎn)double數(shù)等。但是我們有時(shí)也會(huì)遇到多個(gè)枚舉值與數(shù)字互轉(zhuǎn)的情形（例如多個(gè)算法類型枚舉開啟標(biāo)志轉(zhuǎn)成數(shù)字，這個(gè)數(shù)字來表示多個(gè)標(biāo)志位，按位來表示）。這樣一個(gè)數(shù)字就能表示很多個(gè)標(biāo)志位了，針對(duì)內(nèi)存較少的嵌入式設(shè)備，這么操作可以達(dá)到節(jié)約內(nèi)存消耗，提高程序運(yùn)行效率的目的。

Demo示例

demo核心知識(shí)點(diǎn)：通過位運(yùn)算符（布爾位運(yùn)算符："~"、"&"、"|"；移位運(yùn)算符："<<"）實(shí)現(xiàn)int數(shù)與多枚舉值互轉(zhuǎn)。

Code:

#include <iostream>

using namespace std;


int nFlag = 0; //用移位表示各個(gè)枚舉的開關(guān)
typedef enum
{
    TYPEA, //A開啟，則nflag為1=0x00000001
    TYPEB, //B開啟，則nflag為2=0x00000010
    TYPEC, //C開啟，則nflag為4=0x00000100
    TYPED, //D開啟，則nflag為8=0x00001000
    TYPENUM //枚舉最大值，計(jì)數(shù)用
}EMTypeNum;

void int2enum (int n)
{
    if(n&(0x01<<TYPEA))
    {
     //為真
     cout << "TYPEA is ON\n";
    }
    else
    {
     //為假
     cout << "TYPEA is OFF\n";
    }
    
    if(n&(0x01<<TYPEB))
    {
     //為真
     cout << "TYPEB is ON\n";
    }
    else
    {
     //為假
     cout << "TYPEB is OFF\n";
    }
    
    if(n&(0x01<<TYPEC))
    {
     //為真
     cout << "TYPEC is ON\n";
    }
    else
    {
     //為假
     cout << "TYPEC is OFF\n";
    }

    if(n&(0x01<<TYPED))
    {
     //為真
     cout << "TYPED is ON\n";
    }
    else
    {
     //為假
     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

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