Convert 3 digit integer into words using string/array c++

[7h3.doctorat3]

Hi i'm new to using c++ and i would like to ask if you could help me out. I have to somehow get a working c++ program that will allow me to convert any one, two or three digit positive integer into words using string/array method. Say, 111 will be converted into one hundred and eleven. I would greatly appreciate it if you could help me out.

[daviddoria]

I would put the numerical representation of the number into an std::string. From here you can access each digit separately:

std::string number = "123";
std::cout << number[0]; //outputs '1'

You would then have to have a giant switch statement to convert a '1' to "one", etc.

Hope this helps,

Dave

[iamthwee]

Google it. I bet the generic algorithm for this has been done many times before.

If you're only using three digits max it shouldn't be too hard.

For example the following looks like a useful template, written in java though.

http://www.rgagnon.com/javadetails/java-0426.html

#include <iostream>
#include <string>
#include <climits>

class Foo
{
public:
  std::string bar(int number) 
  {
    std::string tensNames[] = {
    "",
    " ten",
    " twenty",
    " thirty",
    " forty",
    " fifty",
    " sixty",
    " seventy",
    " eighty",
    " ninety"
  };

    std::string numNames[] = {
    "",
    " one",
    " two",
    " three",
    " four",
    " five",
    " six",
    " seven",
    " eight",
    " nine",
    " ten",
    " eleven",
    " twelve",
    " thirteen",
    " fourteen",
    " fifteen",
    " sixteen",
    " seventeen",
    " eighteen",
    " nineteen"
  };         
                      
    std::string soFar;

    if (number % 100 < 20)
    {
      soFar = numNames[number % 100];
      number /= 100;
    }
    else 
    {
      soFar = numNames[number % 10];
      number /= 10;

      soFar = tensNames[number % 10] + soFar;
      number /= 10;
    }
    if (number == 0) return soFar + "\n";
    return numNames[number] + " hundred" + soFar + "\n";
  }
};

int main()
{
    Foo bar;
    std::cout << bar.bar(125);
    std::cout << bar.bar(9);
    std::cout << bar.bar(1);
    std::cout << bar.bar(200);
    std::cout << bar.bar(999);
    
    
    std::cin.get();
}

[mrnutty]

If its only 1-3 length, then just hard code it like so :

int toInt(const string& str){
 int result = 0;
 switch(str.length()){
   case 1: result = str[0] - '0'; break;
   case 2: result = (str[0]-'0')*10 + (str[1] - '0'); break;
   case 3: result = (str[0]-'0')*100 + (str[1] - '0')*10 + (str[2] - '0'); break;
   default: /* not supported */ break;
 }
  return result;
}

[daviddoria]

firstPerson - what is this supposed to do? Convert a string to an int? Shouldn't he just use a std::stringstream?

[mrnutty]

firstPerson - what is this supposed to do? Convert a string to an int? Shouldn't he just use a std::stringstream?

sorry misread his post.