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#2
rjsp2023-10-05 14:47
输出的数值不对 你得说说怎么个不对，即“不对”的现象是什么？去除无关代码  程序代码：#include <iostream> 你编译运行一下，把你认为不对的输出贴出来。#include <fstream> using namespace std; int main( void ) { { std::ofstream file( "binary.abc", ios::binary|ios::app ); if( file ) { int a=1, b=2; file.write( reinterpret_cast<char*>(&a), sizeof(a) ); file.write( reinterpret_cast<char*>(&b), sizeof(b) ); } } { std::ifstream file( "binary.abc", ios::binary|ios::app ); if( file ) { int a, b; std::ifstream::traits_type::off_type off = sizeof(a) + sizeof(b); file.seekg( -off,ios::end ); file.read( reinterpret_cast<char*>(&a), sizeof(a) ); file.read( reinterpret_cast<char*>(&b), sizeof(b) ); cout << a << '\n' << b << endl; } } } |
/***********************************
二进制文件数据的读取和写入
***********************************/
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
int age,height,readAge,readHeight;
cout<<"please input age and height:";
cin>>age>>height;
ofstream outBinaryFile("binary.abc",ios::binary|ios::app);
if(outBinaryFile.fail())
{
cout<<"open file failed."<<endl;
exit(0);
}
outBinaryFile.write(reinterpret_cast<char *>(&age),sizeof(age));
outBinaryFile.write(reinterpret_cast<char *>(&height),sizeof(height));
outBinaryFile.close();
ifstream inBinaryFile("binary.abc",ios::binary);
if(inBinaryFile.fail())
{
cout<<"open file failed."<<endl;
exit(0);
}
inBinaryFile.seekg(-sizeof(int)*2,ios::end); //每次读文件，从文件末尾前移两个int字节，不知道对不对，请各位指点
inBinaryFile.read(reinterpret_cast<char *>(&readAge),sizeof(readAge));
inBinaryFile.read(reinterpret_cast<char *>(&readHeight),sizeof(readHeight));
inBinaryFile.close();
cout<<"age from file:"<<readAge<<endl
<<"height from file:"<<readHeight<<endl;
return 0;
}
输出的数值不对