Update 12-9.cpp

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Falling-in-W-sweetty 2022-08-14 11:25:49 +08:00 committed by GitHub
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@ -22,20 +22,20 @@ public:
};
int main(){
ofstream out("D:/Employee.dat",ios::out); //定义随机输出文件
Employee e1(1,"张三",23,2320);
Employee e2(2,"李四",32,3210);
Employee e3(3,"王五",34,2220);
Employee e4(4,"刘六",27,1220);
out.write((char*)&e1,sizeof(e1)); //按e1,e2,e3,e4顺序写入文件
ofstream out("D:/Employee.dat",ios::out); //定义随机输出文件
Employee e1(1,"张三",23,2320);
Employee e2(2,"李四",32,3210);
Employee e3(3,"王五",34,2220);
Employee e4(4,"刘六",27,1220);
out.write((char*)&e1,sizeof(e1)); //按e1,e2,e3,e4顺序写入文件
out.write((char*)&e2,sizeof(e2));
out.write((char*)&e3,sizeof(e3));
out.write((char*)&e4,sizeof(e4));
//下面的代码将e3即王五的年龄改为40岁
Employee e5(3,"王五",40,2220);
out.seekp(3*sizeof(e1)); //指针定位到第3起始为0个数据块
out.write((char*)&e5,sizeof(e5)); //将e5写到第3个数据块位置覆盖e3
out.close(); //关闭文件
//下面的代码将e3即王五的年龄改为40岁
Employee e5(3,"王五",40,2220);
out.seekp(2*sizeof(e1)); //指针定位到第3起始为0个数据块这里写错了应该是2*sizeofe1
out.write((char*)&e5,sizeof(e5)); //将e5写到第3个数据块位置覆盖e3
out.close(); //关闭文件
system("pause");
}
}