test3.cpp

这我们老师对是面向对象程序设计（清华大学出版社）一书制作的PPT

#include<iostream.h>
#include<fstream.h>
#include<stdlib.h>
void main()
{ 
  char ch;
	ifstream ifile("abc.txt");
	ofstream ofile("abc1.txt");
	if(!ifile){cout<<"can't open file"<<endl;
	           exit(1);
	}
	if(!ofile){cout<<"can't open file"<<endl;
	           exit(1);
	}
    ifile.get(ch);
	while (!ifile.eof())
	{	if (ch>='A' && ch<='Z')
			ch+='a'-'A';
		ofile.put(ch);
		ifile.get(ch);

	}
	ofile.close();
	ifile.close();
	
}