Need help with Jumping into C++ - display numbers as text

[borowcy]

Hello, for the past few days I've been stuck on the practice problem in the book Jumping into C++, I'd like to go to further chapters but this task is really hard, for me at least.

Could you give me any help? This is what I've done so far, no idea what I did wrong (probably a lot), what right and what to do next... It's just a big mess.

So far, I only implemented displaying the numbers under lesser than 20.

Thanks in advance, here's the current state of my code.

#include <iostream>
#include <string>


using namespace std;


int main() {
    int input, tens, hundreds, thousands, units;
    string one, two, three, four, five, six, seven, eight, nine, ten;
    string eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen;
    string twenty, thirty, fourty, fifty, sixty, seventy, eighty, ninety;
    string hundred, thousand, million;


    //DATABASE of numbers
    one = "one";
    two = "two";
    three = "three";
    four = "four";
    five = "five";
    six = "six";
    seven = "seven";
    eight = "eight";
    nine = "nine";
    ten = "ten";
    eleven = "eleven";
    twelve = "twelve";
    thirteen = "thirteen";
    fourteen = "fourteen";
    fifteen = "fifteen";
    sixteen = "sixteen";
    seventeen = "seventeen";
    eighteen = "eighteen";
    nineteen = "nineteen";
    twenty = "twenty";
    thirty = "thiry";
    fourty = "fourty";
    fifty = "fifty";
    sixty = "sixty";
    seventy = "seventy";
    eighty = "eighty";
    ninety = "ninety";
    hundred = "hundred";
    thousand = "thousand";
    million = "million";


    cin>> input;


    if ( input > 1000000 || input < -1000000 ) {
        cout<< "The number is out of range!";
    }
    else
    {
        if ( input < 20 )
        {
            switch( input ) {
            case 1:
                cout<< one;
                break;
            case 2:
                cout<< two;
                break;
            case 3:
                cout<< three;
                break;
            case 4:
                cout<< four;
                break;
            case 5:
                cout<< five;
                break;
            case 6:
                cout<< six;
                break;
            case 7:
                cout<< seven;
                break;
            case 8:
                cout<< eight;
                break;
            case 9:
                cout<< nine;
                break;
            case 10:
                cout<< ten;
                break;
            case 11:
                cout<< eleven;
                break;
            case 12:
                cout<< twelve;
                break;
            case 13:
                cout<< thirteen;
                break;
            case 14:
                cout<< fourteen;
                break;
            case 15:
                cout<< fifteen;
                break;
            case 16:
                cout<< sixteen;
                break;
            case 17:
                cout<< seventeen;
                break;
            case 18:
                cout<< eighteen;
                break;
            case 19:
                cout<< nineteen;
                break;
            }
        }
        else {
            units = input - tens*10;
            tens = input / 10;
            hundreds = input / 100;
            thousands = input / 1000;


        }
    }
}

[whiteflags]

I mean, it looks like you got most of it. One through twenty are most of the unique words.

Now you just gotta realize:
howmany = input / 100000; This tells you how many 100 thousands there are, so you can say "x hundred thousand"
howmany = input / 1000; This tells you how many thousands there are, so you can say "xy thousand"
howmany = input / 100; This tells you how many 100s there are so you can say "x hundred yz"

Now you already did 1 through 20, so you should be able to see using howmany that way you can reuse the code that works, and cover lots of numbers.

You can get very fancy with this, but the simplest version to understand (probably) uses recursion:

#include <string>
#include <iostream>
#include <iomanip>


using namespace std;


string explain(long n);


int main()
{
    long tests[] = {0, 11, 43, 266, 1403, 314159, 1000000, -1000000, 1234567890};
    for (size_t i = 0; i < sizeof(tests) / sizeof(tests[0]); ++i) {
        cout << setw(10) << tests[i] << ": " << explain(tests[i]) << endl;
    }
}


string explain(long n) 
{
    const static string words[] = 
    {
        "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", 
        "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", 
        "sixteen", "seventeen", "eighteen", "nineteen", "twenty", "thirty", 
        "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
    };
    
    if (n < -1000000 || n > 1000000) return "unsupported";
    
    string out;
    if (n < 0) {
        out = "minus ";
        n = -n;
    }
    
    if (n == 1000000) return out + "one million";
    else if (n >= 1000) {
        out = out + explain(n / 1000) + " thousand";
        n %= 1000;

        if (n > 0) out = out + ' ' + explain(n);
    }
    else if (n >= 100) {
        out = out + words[n / 100] + " hundred";
        n %= 100;
        
        if (n > 0) out = out + ' ' + explain(n);
    }
    else if (n >= 20) {
        out += words[n / 10 + 18];
        n %= 10;

        if (n > 0) out = out + '-' + words[n]; 
    }
    else out += words[n];

    return out;
 }


         0: zero
        11: eleven
        43: forty-three
       266: two hundred sixty-six
      1403: one thousand four hundred three
    314159: three hundred fourteen thousand one hundred fifty-nine
   1000000: one million
  -1000000: minus one million
1234567890: unsupported

That's very convertible to your own algorithm, I think.

[Tien Nguyen]

I mean, it looks like you got most of it. One through twenty are most of the unique words.

Now you just gotta realize:
howmany = input / 100000; This tells you how many 100 thousands there are, so you can say "x hundred thousand"
howmany = input / 1000; This tells you how many thousands there are, so you can say "xy thousand"
howmany = input / 100; This tells you how many 100s there are so you can say "x hundred yz"

Now you already did 1 through 20, so you should be able to see using howmany that way you can reuse the code that works, and cover lots of numbers.

You can get very fancy with this, but the simplest version to understand (probably) uses recursion:

#include <string>
#include <iostream>
#include <iomanip>


using namespace std;


string explain(long n);


int main()
{
    long tests[] = {0, 11, 43, 266, 1403, 314159, 1000000, -1000000, 1234567890};
    for (size_t i = 0; i < sizeof(tests) / sizeof(tests[0]); ++i) {
        cout << setw(10) << tests[i] << ": " << explain(tests[i]) << endl;
    }
}


string explain(long n) 
{
    const static string words[] = 
    {
        "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", 
        "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", 
        "sixteen", "seventeen", "eighteen", "nineteen", "twenty", "thirty", 
        "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
    };
    
    if (n < -1000000 || n > 1000000) return "unsupported";
    
    string out;
    if (n < 0) {
        out = "minus ";
        n = -n;
    }
    
    if (n == 1000000) return out + "one million";
    else if (n >= 1000) {
        out = out + explain(n / 1000) + " thousand";
        n %= 1000;

        if (n > 0) out = out + ' ' + explain(n);
    }
    else if (n >= 100) {
        out = out + words[n / 100] + " hundred";
        n %= 100;
        
        if (n > 0) out = out + ' ' + explain(n);
    }
    else if (n >= 20) {
        out += words[n / 10 + 18];
        n %= 10;

        if (n > 0) out = out + '-' + words[n]; 
    }
    else out += words[n];

    return out;
 }


         0: zero
        11: eleven
        43: forty-three
       266: two hundred sixty-six
      1403: one thousand four hundred three
    314159: three hundred fourteen thousand one hundred fifty-nine
   1000000: one million
  -1000000: minus one million
1234567890: unsupported

That's very convertible to your own algorithm, I think.

Congrats.

[Tien Nguyen]

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>


int main()
{
long numbers, tempx, tempy;


scanf("%D", &numbers);
if(numbers == 0)
{
printf("\n zero");
}


tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;


if(numbers == 1)
{
printf("\n one");
}


if(numbers == 2)
{
printf("\n two");
}


if(numbers == 3)
{
printf("\n three");
}


if(numbers == 4)
{
printf("\n four");
}
if(numbers == 5)
{
printf("\n five");
}
if(numbers == 6)
{
printf("\n six");
}
if(numbers == 7)
{
printf("\n seven");
}
if(numbers == 8)
{
printf("\n eight");
}
if(numbers == 9)
{
printf("\n nine");
}


numbers = tempx;


if(numbers > 9)
{
numbers = numbers/10;
tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;
}
else
{
goto exitroutine;
}


if(numbers == 1)
{
printf("\n ten");
}
if(numbers == 2)
{
printf("\n twenty");
}
if(numbers == 3)
{
printf("\n thirty");
}
if(numbers == 4)
{
printf("\n fourty");
}
if(numbers == 5)
{
printf("\n fifty");
}
if(numbers == 6)
{
printf("\n sixty");
}
if(numbers == 7)
{
printf("\n seventy");
}
if(numbers == 8)
{
printf("\n eighty");
}
if(numbers == 9)
{
printf("\n ninety");
}


numbers = tempx;


numbers = numbers/10;
tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;


if(tempx > 0)
{
goto process;
}
else
{
goto exitroutine;
}


process:;
if(numbers == 0)
{
goto preprocess1000;
}


if(numbers == 1)
{
printf("\n one");
}


if(numbers == 2)
{
printf("\n two");
}


if(numbers == 3)
{
printf("\n three");
}


if(numbers == 4)
{
printf("\n four");
}
if(numbers == 5)
{
printf("\n five");
}
if(numbers == 6)
{
printf("\n six");
}
if(numbers == 7)
{
printf("\n seven");
}
if(numbers == 8)
{
printf("\n eight");
}
if(numbers == 9)
{
printf("\n nine");
}


printf(" hundred");


preprocess1000:;


numbers = tempx;
numbers = numbers/10;


if(numbers > 0)
{
tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;


goto process1000;
}
else
{
goto exitroutine;
}


process1000:;
if(numbers == 0)
{
goto preprocess10000;
}


if(numbers == 1)
{
printf("\n one");
}


if(numbers == 2)
{
printf("\n two");
}


if(numbers == 3)
{
printf("\n three");
}


if(numbers == 4)
{
printf("\n four");
}
if(numbers == 5)
{
printf("\n five");
}
if(numbers == 6)
{
printf("\n six");
}
if(numbers == 7)
{
printf("\n seven");
}
if(numbers == 8)
{
printf("\n eight");
}
if(numbers == 9)
{
printf("\n nine");
}


printf(" thousand");


numbers = tempx;


preprocess10000:;


numbers = tempx;
numbers = numbers/10;


if(numbers > 0)
{
tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;


goto process10000;
}
else
{
goto exitroutine;
}


process10000:;
if(numbers == 0)
{
goto preprocess100000;
}


if(numbers == 1)
{
printf("\n ten");
}
if(numbers == 2)
{
printf("\n twenty");
}
if(numbers == 3)
{
printf("\n thirty");
}
if(numbers == 4)
{
printf("\n fourty");
}
if(numbers == 5)
{
printf("\n fifty");
}
if(numbers == 6)
{
printf("\n sixty");
}
if(numbers == 7)
{
printf("\n seventy");
}
if(numbers == 8)
{
printf("\n eighty");
}
if(numbers == 9)
{
printf("\n ninety");
}


printf(" thousand");


numbers = tempx;


preprocess100000:;


numbers = tempx;
numbers = numbers/10;


if(numbers > 0)
{
tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;


goto process100000;
}
else
{
goto exitroutine;
}


process100000:;
if(numbers == 0)
{
goto preprocess1000000;
}


if(numbers == 1)
{
printf("\n one");
}


if(numbers == 2)
{
printf("\n two");
}


if(numbers == 3)
{
printf("\n three");
}


if(numbers == 4)
{
printf("\n four");
}
if(numbers == 5)
{
printf("\n five");
}
if(numbers == 6)
{
printf("\n six");
}
if(numbers == 7)
{
printf("\n seven");
}
if(numbers == 8)
{
printf("\n eight");
}
if(numbers == 9)
{
printf("\n nine");
}


printf(" hundred thousand");


numbers = tempx;


preprocess1000000:;


numbers = tempx;
numbers = numbers/10;


if(numbers > 0)
{
tempx = numbers/10*10;
tempy = numbers - tempx;
tempx = numbers;
numbers = tempy;


goto process1000000;
}
else
{
goto exitroutine;
}


process1000000:;
if(numbers == 0)
{
goto exitroutine;
/*
goto preprocess10000000;
*/
}


if(numbers == 1)
{
printf("\n one");
}


if(numbers == 2)
{
printf("\n two");
}


if(numbers == 3)
{
printf("\n three");
}


if(numbers == 4)
{
printf("\n four");
}
if(numbers == 5)
{
printf("\n five");
}
if(numbers == 6)
{
printf("\n six");
}
if(numbers == 7)
{
printf("\n seven");
}
if(numbers == 8)
{
printf("\n eight");
}
if(numbers == 9)
{
printf("\n nine");
}


printf(" million");


numbers = tempx;


exitroutine:;
}

[Salem]

Mmm,

A 40 line function (nicely indented, easy to read, VERY easy to extend to cover billions)

vs

A 500+ line horror of unindented code riddled with goto statements.