ifstream object.eof()不工作 [英] ifstream object.eof() not working
问题描述
我想我可能需要为我的while条件使用布尔值bValue = false:
char cArray [100] = ;
pre>
ifstream object
cout<< 输入完整路径名:;
cin.getline(cArray,100);
if(!object)return -1 //路径无效?这个语句执行为什么?
ifstream object.open(cArray,100);
//读取文本文件的内容,直到我们点击eof。
while(!object.eof())
{
//解析这里的文件
}
为什么我不能输入文本文件的完整路径名?
这可能是因为eof。
可以有:
code> while(!object == true)
{
//文件的parase内容
}
解决方案请大家和其他人一起注意,读取文本文件的正确方法不需要使用eof() (),bad()或indifferent()函数(OK,我做了最后一个)。在C中也是这样(使用fgets(),feof()等)。基本上,这些标志只有在你试图读取东西后,使用getline()函数设置。它更简单,更可能是正确的测试读函数,如getline()实际上直接读取的东西。
未测试 - 我升级我的编译器:
#include< iostream>
#include< fstream>
#include< string>
using namespacr std;
imt main(){
string filename;
getline(cin,filename);
ifstream ifs(filename.c_str());
if(!ifs.is_open()){
//错误
}
string行;
while(getline(ifs,line)){
//使用行
执行操作}
}
I think i might need to use a boolean bValue = false for my while condition:
char cArray[ 100 ] = ""; ifstream object; cout << "Enter full path name: "; cin.getline( cArray, 100 ); if ( !object ) return -1 // Path is not valid? This statement executes why? ifstream object.open( cArray, 100 ); // read the contents of a text file until we hit eof. while ( !object.eof() ) { // parse the file here }
Why can i not enter the full path name of the text file?
It might be because of the eof. Is their syntax for a boolean statement that can emulate eof?
Can i have:
while ( !object == true ) { // parase contents of file }
解决方案Please will you and everyone else note that the correct way to read a text file does NOT require the use of the eof(), good(), bad() or indifferent() functions (OK, I made the last one up). The same is true in C (with fgets(), feof() et al). Basically, these flags will only be set AFTER you have attempted to read something, with a function like getline(). It is much simpler and more likely to be correct to test that read functions, like getline() have actually read something directly.
Not tested - I'm upgrading my compiler:
#include <iostream> #include <fstream> #include <string> using namespacr std; imt main() { string filename; getline( cin, filename ); ifstream ifs( filename.c_str() ); if ( ! ifs.is_open() ) { // error } string line; while( getline( ifs, line ) ) { // do something with line } }
这篇关于ifstream object.eof()不工作的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!