shiti6_5_1.cpp

为初学者提供的最佳的C++程序设计源程序库

#include<iostream.h>
#include<fstream.h>
#include<stdlib.h>
struct student 
{
	int no;
	char name[10];
	double degree;
};
struct student stu[3]={1,"张三",90,5,"李四",84,5,9,"王五",79};
void main()
{
	int i;
	student temp;
	fstream infile,outfile;
	outfile.open("data.dat",ios::out|ios::trunc|ios::binary);
	if(!outfile)
	{
		cout<<"can't open the file."<<endl;
		abort();
	}
	for(i=0;i<3;i++)
		outfile.write((char *)&stu[i],sizeof(stu[i]));
	outfile.close();
	cout<<"data.dat的内容如下："<<endl;
	infile.open("data.dat",ios::in|ios::binary);
	for(i=0;i<3;i++)
	{
		infile.read((char *)&stu[i],sizeof(stu[i]));
		cout<<stu[i].no<<"\t"<<stu[i].name<<"\t"<<stu[i].degree<<endl;
	}
	infile.close();
	cout<<"删除第二个记录后，data.dat的内容如下："<<endl;
    outfile.open("data.dat",ios::out|ios::trunc|ios::binary);
	for(i=0;i<3;i++)
		if(i!=1)
			outfile.write((char *)&stu[i],sizeof(stu[i]));
		outfile.close();
		infile.open("data.dat",ios::in|ios::binary);
	for(i=0;i<2;i++)
	{
		infile.read((char *)&stu[i],sizeof(stu[i]));
		cout<<stu[i].no<<"\t"<<stu[i].name<<"\t"<<stu[i].degree<<endl;
	}
	infile.close();
	cout<<"请输入记录号：";
	cin>>i;
	infile.open("data.dat",ios::in|ios::binary);
	int pos=(i-1)*sizeof(student);
	infile.seekg(pos);
	infile.read((char *)&temp,sizeof(student));
	cout<<"记录"<<i<<"如下:"
		<<temp.no<<"\t"<<temp.name<<"\t"<<temp.degree<<endl;
	infile.close();
}