Question

我有一个名为aisha的文本文件

This is a new file I did it for mediu.
Its about Removing stopwords fRom the file
and apply casefolding to it
I Tried doing that many Times
and finally now I could do

我做了一个代码来读取该文本文件并将其保存到一个数组中，然后将一些字符转换为低位字符但我想要的是让代码将文件读作字符串而不是字符

char myArray[200];

是

`string myArray[200];`

我想我可以使用函数tolower()和字符串std来完成它我用了很长的代码但我不知道如何将我的代码更改为使用该函数的代码

我的代码是

#include <iostream>
#include <string>
#include <fstream>
#include<ctype.h>
int main()
{
    using namespace std;

    ifstream file("aisha.txt");
    if(file.is_open())
    {
        file >> std::noskipws;
         char myArray[200];

        for(int i = 0; i < 200; ++i)
        {


            cout<<"i";
            if (myArray[i]=='A')
            cout<<"a";
            if (myArray[i]=='T')
            cout<<"t";
            if (myArray[i]=='R')
            cout<<"r";
            else 
            if (myArray[i]!='I' && myArray[i]!='T' && myArray[i]!='R'&& myArray[i]!='A')
            cout<<myArray[i];
            }
         file.close();

        }

system("PAUSE");
return 0;
}

我在这个网站上看到了这个解决方案但我无法将其应用于我的代码

#include <boost/algorithm/string.hpp>    

std::string str = "wHatEver";
boost::to_lower(str);

Otherwise, you may use std::transform:

std::string str = "wHatEver";
std::transform(str.begin(), str.end(), str.begin(), ::tolower);

Answer 1

以下代码可以解决您的问题：

#include <iostream>
#include <iomanip>
#include <fstream>
#include <sstream>
#include <string>
#include <cctype>
#include <algorithm>
#include <iterator>

using namespace std;

int main(int argc, char **argv) {
    ifstream ifs("file");
    ostringstream oss;
    char c;
    while(true)     {
            c = ifs.get();
            if(ifs.good())
                    oss.put(c);
            else
                    break;
    }
    string s = oss.str();
    transform(s.begin(), s.end(), ostream_iterator<char>(cout), ::tolower);
    return 0;
}

Answer 2

1）我希望这个例子可以帮助你

#include "stdafx.h"
#include "iostream"
#include <stdio.h>
#include <ctype.h>
using namespace std;
int main ()
{
int i=0;
char str[30]="TESt STRING.\n";
 char c;
   while (str[i])
  {
   c=str[i];
   str[i]= (tolower(c));
cout<<str[i];
     i++;
    }

  return 0;
  }

Answer 3

有多种方法可以做到这一点。最后你想要一个容器，容器是输入文件数据的所有小写字符串，它是相当简单的。这里使用的算法的前提是：

使用std::istream_iterator<std::string>对从输入文件加载字符串向量。
使用std::for_each算法枚举向量中的每个字符串，执行自定义操作。
我们正在执行的自定义操作是枚举当前字符串中的每个字符，将字符转换为小写等效字符。

最后，代码看起来像这样：

#include <iostream>
#include <fstream>
#include <iterator>
#include <algorithm>
#include <vector>
#include <string>
#include <cctype>

// transform a string in-place to lower case
struct StrLower
{
    void operator()(std::string& s) const
    {
        for (std::string::iterator it = s.begin(); it != s.end(); ++it)
            *it = static_cast<char>(std::tolower(static_cast<unsigned char>(*it)));
    }
};

int main(int argc, char *argv[])
{
    // build a vector of std::string from the input file
    std::ifstream inf("aisha.txt");
    std::vector<std::string> data (
        (std::istream_iterator<std::string>(inf)),
         std::istream_iterator<std::string>());

    // for each string in the vector, transform to lower case.
    for_each(data.begin(), data.end(), StrLower());

    // display all the transformed strings
    std::copy(data.begin(), data.end(),
        std::ostream_iterator<std::string>(std::cout, "\n"));

    return 0;
}

输入（aisha.txt）

This is a new file I did it for mediu.
Its about Removing stopwords fRom the file
and apply casefolding to it
I Tried doing that many Times
and finally now I could do

<强>输出

this
is
a
new
file
i
did
it
for
mediu.
its
about
removing
stopwords
from
the
file
and
apply
casefolding
to
it
i
tried
doing
that
many
times
and
finally
now
i
could
do

希望能帮到你。

Answer 4

请在此处查看解决方案： std::tolower and Visual Studio 2013

例如，你可以这样做：

std::transform(test.begin(), test.end(), test.begin(),
               [](unsigned char c) { return std::tolower(c); });

使用c ++中的tolower（）函数将字符串转换为小写字符

4 个答案: