How to add dot character to a character in string?

Question

I want to add '.' character besides another character in a string but I don't know how to do it ? is it possible?

#include <iostream>

#include <string.h>

using namespace std;

int main(int argc, char *argv[]) {

    string input;
    char dot='.';
    cin>>input;
    for(int i=0;i<input.length();i++)
    {

        if( input[i]>=65 && input[i]<=90)
                {
                    input[i]=input[i]+32;   
                }
        if( (input[i]=='a') || (input[i]=='e') || (input[i]=='i') ||  (input[i]=='o') || input[i]=='y'  || input[i]=='u' )
        {
            input.erase(i,i+1);
        }
        input[i]+=dot;
    }
    cout<<input<<endl;
    return 0;
}

Answer 1

From the cpluplus.com reference ( http://www.cplusplus.com/reference/string/string/insert/ )

// inserting into a string
#include <iostream>
#include <string>
using namespace std;

int main ()
{
  string str="to be question";
  string str2="the ";
  string str3="or not to be";
  string::iterator it;

  // used in the same order as described above:
  str.insert(6,str2);                 // to be (the )question
  str.insert(6,str3,3,4);             // to be (not )the question
  str.insert(10,"that is cool",8);    // to be not (that is )the question
  str.insert(10,"to be ");            // to be not (to be )that is the question
  str.insert(15,1,':');               // to be not to be(:) that is the question
  it = str.insert(str.begin()+5,','); // to be(,) not to be: that is the question
  str.insert (str.end(),3,'.');       // to be, not to be: that is the question(...)
  str.insert (it+2,str3.begin(),str3.begin()+3); // (or )

  cout << str << endl;
  return 0;
}

Also, check these links:

http://www.cplusplus.com/reference/string/string/ http://www.cplusplus.com/reference/string/string/append/ http://www.cplusplus.com/reference/string/string/push_back/

Answer 2

Before you try writing the code, you should write a detailed specification of what it is supposed to do. With your code, I can only guess: convert to lower case (naïvely, pretending that you'll only encounter the 26 unaccented letters in ASCII), then delete all vowels (again, very naïvely, since determining whether something is a vowel or not is non-trivial, even in English—consider the y in yet and day), and finally inserting a dot after each character. The most obvious way of doing that would be something like:

std::string results;
for ( std::string::const_iterator current = input.begin(),
                end = input.end();
        current != end;
        ++ current ) {
    static std::string const vowels( "aeiouAEIOU" );
    if ( std::find( vowels.begin(), vowels.end(), *current )
                != vowels.end() ) {
        results.push_back(
            tolower( static_cast<unsigned char>( *current ) ) );
    }
    results.push_back( '.' );
}

But again, I'm just guessing as to what you are trying to do.

Another alternative would be to use std::transform on the initial string to make it all lower case. If you're doing this sort of thing regularly, you'll have a ToLower functional object; otherwise, it's probably too much of a bother to write one just to be able to use std::transform once.

Answer 3

I’m assuming you want this input:

Hello world!

To give you this output:

h.ll. w.rld!

Rather than trying to modify the string in place, you can simply produce a new string as you go:

#include <cctype>
#include <iostream>
#include <string>
using namespace std;

int main(int argc, char *argv[]) {
    string input;
    getline(cin, input);
    string output;
    const string vowels = "aeiouy";
    for (int i = 0; i < input.size(); ++i) {
        const char c = tolower(input[i]);
        if (vowels.find(c) != string::npos) {
            output += '.';
        } else {
            output += c;
        }
    }
    cout << output << '\n';
    return 0;
}

Notes:

• <cctype> is for toupper().

• <string.h> is deprecated; use <string>.

• Read whole lines with getline(); istream::operator>>() reads words.

• Use tolower(), toupper(), &c. for character transformations. c + 32 doesn’t describe your intent.

• When you need comparisons, c >= 'A' && c <= 'Z' will work; you don't need to use ASCII codes.

• Use const for things that will not change.

Answer 4

Based on your comments, it sounds like you want something like this:

#include <iostream>
#include <string>
#include <algorithm>

int main(int argc, char *argv[])
{
    std::string input;
    std::cin >> input;

    std::transform (input.begin(), input.end(), input.begin(), tolower);

    size_t i = 0;
    while (i < input.length())
    {
        switch (input[i])
        {
            case 'a':
            case 'e':
            case 'i':
            case 'o':
            case 'y':
            case 'u':
            {
                size_t pos = input.find_first_not_of("aeioyu", i+1);
                if (pos == std::string::npos)
                  pos = input.length();
                input.erase(i, pos-i);
                break;
            }

            default:
            {
                input.insert(i, '.');
                i += 2;
                break;
            }
        }
    }

    std::cout << input << std::endl;
    return 0;
}