convert strings to lowercase characters using tolower() function in c++

Question

I have a text file called aisha

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

and I did a code to read that text file and save it into an array and then convert some characters to lowrcase but what I want is to to make the codes reads the file as a string not char

char myArray[200];

to be

`string myArray[200];`

I think I can do it using the function tolower()and a string std insted that long code I used but I dont know how to change my code to a code that uses that functions

my code is

#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;
}

I saw that solution in this site but I couldnt apply it to my code

#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

The following code can solve your problem:

#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)i hope this example helps you

#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

The are any number of ways to do this. In the end you want a container that container all lower-case strings of the input file data, it is fairly straight-forward. The premise of the algorithm used here is:

• use a std::istream_iterator<std::string> pair to load a vector of strings from the input file.
• use the std::for_each algorithm to enumerate over each string in the vector, performing a custom action.
• the custom action we're performing is to enumerate over each character in the current string, transforming the character to its lower-case equivalence.

In the end, the code looks something like this:

#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;
}

Input (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

Output

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

Hope that helps you out.

Answer 4

See the solutions here: std::tolower and Visual Studio 2013

For example, you could do:

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