我要做的是输入一个LINE BY LINE文件并将其标记并输出到输出文件中。我能够做的是输入文件中的第一行但我的问题是我无法输入下一行标记,以便它可以保存为输出文件中的第二行,这是我到目前为止输入文件中第一行所能做的。
#include <iostream>
#include<string> //string library
#include<fstream> //I/O stream input and output library
using namespace std;
const int MAX=300; //intialization a constant called MAX for line length
int main()
{
ifstream in; //delcraing instream
ofstream out; //declaring outstream
char oneline[MAX]; //declaring character called oneline with a length MAX
in.open("infile.txt"); //open instream
out.open("outfile.txt"); //opens outstream
while(in)
{
in.getline(oneline,MAX); //get first line in instream
char *ptr; //Declaring a character pointer
ptr = strtok(oneline," ,");
//pointer scans first token in line and removes any delimiters
while(ptr!=NULL)
{
out<<ptr<<" "; //outputs file into copy file
ptr=strtok(NULL," ,");
//pointer moves to second token after first scan is over
}
}
in.close(); //closes in file
out.close(); //closes out file
return 0;
}
答案 0 :(得分:15)
C++ String Toolkit Library (StrTk)针对您的问题提供了以下解决方案:
#include <iostream>
#include <string>
#include <deque>
#include "strtk.hpp"
int main()
{
std::deque<std::string> word_list;
strtk::for_each_line("data.txt",
[&word_list](const std::string& line)
{
const std::string delimiters = "\t\r\n ,,.;:'\""
"!@#$%^&*_-=+`~/\\"
"()[]{}<>";
strtk::parse(line,delimiters,word_list);
});
std::cout << strtk::join(" ",word_list) << std::endl;
return 0;
}
可以找到更多示例Here
答案 1 :(得分:1)
当C ++使这个更整洁时,你正在使用C运行库。
在C ++中执行此操作的代码:
ifstream in; //delcraing instream
ofstream out; //declaring outstream
string oneline;
in.open("infile.txt"); //open instream
out.open("outfile.txt"); //opens outstream
while(getline(in, oneline))
{
size_t begin(0);
size_t end;
do
{
end = oneline.find_first_of(" ,", begin);
//outputs file into copy file
out << oneline.substr(begin,
(end == string::npos ? oneline.size() : end) - begin) << ' ';
begin = end+1;
//pointer moves to second token after first scan is over
}
while (end != string::npos);
}
in.close(); //closes in file
out.close(); //closes out file
输入:
a,b c
de fg,hijklmn
输出:
a b c de fg hijklmn
如果您想要换行,请在适当的位置添加out << endl;
。