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示例
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:1TYPEA is ONTYPEB is OFFTYPEC is OFFTYPED is OFF
nFlag:3TYPEA is ONTYPEB is ONTYPEC is OFFTYPED is OFF
nFlag:7TYPEA is ONTYPEB is ONTYPEC is ONTYPED is OFF
nFlag:15TYPEA is ONTYPEB is ONTYPEC is ONTYPED is ON
nFlag:14TYPEA is OFFTYPEB is ONTYPEC is ONTYPED is ON
nFlag:12TYPEA is OFFTYPEB is OFFTYPEC is ONTYPED is ON
nFlag:8TYPEA is OFFTYPEB is OFFTYPEC is OFFTYPED is ON
nFlag:0TYPEA is OFFTYPEB is OFFTYPEC is OFFTYPED is OFF
到此这篇关于C/C++ int数与多枚举值互转的实现的文章就介绍到这了,更多相关C++ int数与多枚举值互转内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持！
不敢接受失败的人，往往是那些追求完美的人，
