C++快速入门 第十一讲：结构

结构是一种由程序员自己定义的、由其他变量类型组合而成的数据类型。其所能包含的变量的个数是没有限制的。

实例1：简单数据库读写

  1 #include <iostream>
  2 #include <fstream>  //文件操作 
  3 #include <windows.h>        // 为了使用Sleep()函数 
  4 
  5 struct FishOil
  6 {
  7         std::string name;
  8         std::string uid;
  9         char sex;
 10 }; 
 11 
 12 bool InitFishC();
 13 bool ReadFishC(); 
 14 void RecordFishC();
 15 bool WriteFishC(FishOil *OilData);
 16 
 17 int main()
 18 {
 19         int i;
 20         
 21         InitFishC();  // 初始化数据。 
 22         while( 1 )
 23         { 
 24                 std::cout << "请选择需要进行的操作: \n";
 25                 std::cout << "1. 打印数据到屏幕\n";
 26                 std::cout << "2. 录入数据\n"; 
 27                 std::cout << "3. 退出程序\n"; 
 28                 std::cin >> i;
 29                 
 30                 switch( i )
 31                 {
 32                         case 1: 
 33                                 if( ReadFishC() )
 34                                         std::cout << "成功读取文件^_^\n\n";
 35                                 else
 36                                         std::cout << "读取文件失败T_T\n\n";
 37                                 break;
 38                         case 2:
 39                                 RecordFishC();
 40                                 break;
 41                         case 3:
 42                                 return 0;        
 43                 }
 44         }
 45         
 46         return 0;
 47         
 48 }
 49 
 50 bool InitFishC()
 51 {
 52         FishOil OilInit = {"小甲鱼", "fishc00001", 'M'};
 53 
 54         if( WriteFishC(&OilInit) == false )
 55                 std::cout << "初始化失败T_T\n";  
 56 } 
 57 
 58 bool ReadFishC() //读文件 
 59 {
 60         std::string temp;
 61         std::ifstream fileInput("FishC.txt");
 62         
 63         if(  fileInput.is_open() )
 64         {
 65                 std::cout << "\n正在输出记录数据...... ";
 66                 for( int i=0; i <= 100; i++ )      // 打印百分比 
 67                 {
 68                         std::cout.width(3);
 69                         std::cout << i << "%";
 70                         Sleep(50);
 71                         std::cout << "\b\b\b\b";
 72                 }
 73                 std::cout << "\n\n";
 74                 
 75 
 76                 std::cout << " 姓名 " << "  身份证  " << " 性别 " << "\n\n";
 77                  
 78                 while( std::getline( fileInput, temp ) )
 79                 {
 80                         std::cout << temp << "   ";
 81                         std::cout << "\n";
 82                 }
 83                 std::cout << "\n\n";
 84                 
 85                 return true;
 86         } 
 87         else
 88                 return false;
 89 }
 90 
 91 void RecordFishC()//录入数据 
 92 {
 93         char goon, Save;
 94         FishOil OilData;
 95         FishOil *pOilData;
 96         
 97         goon = 'Y';
 98         while( 'Y' == goon )
 99         {
100                 std::cout << "请输入鱼C账号: ";
101                 std::cin >> OilData.name;
102                 std::cout << "请输入鱼C身份证：";
103                 std::cin >> OilData.uid;
104                 std::cout << "请输入性别：";
105                 std::cin >> OilData.sex;
106                 
107                 std::cout << "录入成功, 请问需要保存吗？（Y/N）";
108                 std::cin >> Save;         
109                 if( 'Y' == Save )
110                 {
111                         pOilData = &OilData;
112                         if( WriteFishC( pOilData ) )
113                                 std::cout << "成功写入文件^_^\n";
114                         else
115                                 std::cout << "写入文件失败T_T\n";        
116                 }
117                 else
118                 {
119                         return;
120                 }
121                 
122                 std::cout << "/n请问需要再次录入吗？（Y/N）";
123                 std::cin >> goon; 
124         }
125 }
126 
127 bool WriteFishC( FishOil *pOilData )//写文件 
128 {
129         std::ofstream fileOutput("FishC.txt", std::ios::app);  
130                 // std::ios::app用来说明在老数据追加新数据 
131         if( fileOutput.is_open() )
132         {
133                 fileOutput << pOilData->name << " ";
134                 fileOutput << pOilData->uid << " ";
135                 fileOutput << pOilData->sex << "\n";
136                 
137                 fileOutput.close();
138                 std::cout << "数据成功保存到FishC.txt\n\n";
139                 return true; 
140         } 
141         else
142                 std::cout << "保存失败T_T\n";
143                 return false;         
144 }