Spelling Out Numbers

Code:

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//Program requires user to enter a number
//program should then print out the name of each digit
//I cant seem to get my program to work it keeps spelling out
//each digit as "zero"
//does anyone see any mistakes?
//sorry Im a newbie at this.

#include<stdio.h>
#include <math.h>
int main(void)
{
 
 
  long long int n,k,i,d,a;
 
 
 
  printf("please enter your phone number: ");
  scanf("%llu",&n);
  a=n;
 
    for ( i=0; n>0; i++)            //for loop   
        {  n=n/10;  }
   
    for (k=i; k>=1; k--)
      { d=n/pow(10,k-1);     
   
 
  switch (n)
    {
  case 0:
  printf("zero");
  break;
 
  case 1:
  printf("one");
  break;
 
  case 2:
  printf("two");
  break;
 
  case 3:
  printf("three");
  break;
 
  case 4:
  printf("four");
  break;
 
  case 5:
  printf("five");
  break;
 
  case 6:
  printf("six");
  break;
 
  case 7:
  printf("seven");
  break;
 
  case 8:
  printf("eight");
  break;
 
  case 9:
  printf("nine");
  break; }
 
  a=a-d*pow(10,k-1);
 
  }
 
  return(0);
  }

---

d=n/pow(10,k-1);
switch (n)

Are you sure?

Do you know about / are you allowed to use arrays?

No, we have not learned arrays yet.

I have no idea what you're trying to do with pow(), OK.

Normal idiom would be to % 10, and save the result, for use in your switch statement.

You can't save it as n, (maybe name it digit), because you're using n<0; as your test condition in the for loop.

Then divide n by 10, and loop back.

logic:

Code:

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while n is > 0 (for loop is fine, also)
  digit = n mod 10
  switch (digit) {
  };
  n = n divided by 10
end of loop

---

While i, j, n and x, are very standard variable names for simple loop counter or indexers, or numbers, using single letters which have no bearing on the use of the variable, is a terrible idea. Make your variable names *meaningful* names.

We have the memory to add a great deal of clarity to our programs, by doing this. Why not use it?

P.S. It doesn't matter where you divide n by 10, as long as you do it AFTER the mod statement.

Think about when this loop will stop:

Code:

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    for ( i=0; n>0; i++)            //for loop   
        {  n=n/10;  }

---

It will stop when n is not greater than zero. What cases are those? Well considering that n is only ever reduced in magnitude and thus will not become negative, the only option is zero.
Ooops!?!

Both run OK.

Code:

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#include <stdio.h>

int main(void) {
 
  int n=1234567, digit;

  printf("\nWhile loop:\n");
  while(n>0) {
      digit = n % 10;
      printf("%d\n", digit);
      n /= 10;
  }
  //or
  n = 1234567;
  printf("\nFor loop:\n");
  for(;n>0;) {
      digit = n % 10;
      printf("%d\n", digit);
      n /= 10;
  }
  return 0;
}

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