Thread: Complex C questions

I am ok at programming but I don't get how to compare the number back to check if it's composed of the same numbers in this problem. Even general tips would b super!,
i have so far made a function for multiplying the user inputted number to obtain the number that will need testing for whether it is an anagram or notI am however aware that it has quite a lot wrong with it :P I have other code but this is a little annoying. Also how can I compare the numbers within the user inputted number (if that makes sense)

Code:

void multiplyNumber(int userInput)

while(multiplyBy<9)
{
	int multiplyBy = 2;
	userInput*multiplyBy = anagramToTest1;
	multiplyBy++;

}

An anagram number is a number that can be multiplied by at least one single digit number (other than 1)
to become an anagram of itself. Any anagrams formed by multiplying an anagram number by a digit are
said to be generated by that anagram number. Two numbers are anagrams of each other if they can both
be formed by rearranging the same combination of digits.
For example:
• 1246878 is an anagram number; multiplying by 6 generates 7481268 or by 7 generates 8728146.
These numbers all contain a single 1, 2, 4, 6, 7 and two 8s.
• 1246879 is not an anagram number.
1(a)
Write a program which reads in a single number (between 1 and 123456789 inclusive)
and determines if it is an anagram number.
If the number is not an anagram number you should output the word NO. If it is an
anagram number you should output each single digit it can be multiplied by to make
an anagram of itself.

You could create two arrays that keep counts of the digits in each number:

Code:

void count_digits(int num, int *values)
{
  while(num)
  {
    values[num % 10]++;
    num /= 10;
  }
}

int main(void)
{
  int num1 = 1246878;
  int num2 = 8728146;
  int num1values[10];
  int num2values[10];
  int i;

  count_digits(num1, num1values);
  count_digits(num2, num2values);

  for(i = 0;i < 10;++i)
    if(num1values[i] != num2values[i])
   {
      puts("Not an anagram number");
      break;
    }

  if(i == 10)
    puts("It is an anagram");

  return 0;
}

That would test one number against another anyway. I haven't tested the code so there might be errors. You get the idea though.

Originally Posted by nonoob

We shouldn't be doing the entire homework assignment for people. As a poster of 2450+ posts you should know that.

It's not the entire homework assignment. Look again.

Basically, it's keeping a count of each digit of the number in an array. When count_digits() returns, values[0] will have the number of 0s in the number, values[1] will have the number of 1s, etc. Then you just compare the arrays.

Ok I'm getting somewhere here, however, to make my code more efficient and better, if for example I have created a function (just a small bit of my program) how can I , without copying it out many times, make sure that when the userInput is multiplied by the multiplyBy value, every time this loops it will store the result of the subsequent operation in different variable names (e.g anagramToTest1,2,3,4 etc...)

Code:

void multiplyNumber(int userInput)

while(multiplyBy<9)
{
	int multiplyBy = 2;
	userInput*multiplyBy = anagramToTest1;
	multiplyBy++;

}

<< !! Posting Code? Read this First !! >>
Then edit your post if you still can, and make your code as readable as Post #3

Originally Posted by alexbcg

Ok I'm getting somewhere here, however, to make my code more efficient and better, if for example I have created a function (just a small bit of my program) how can I , without copying it out many times, make sure that when the userInput is multiplied by the multiplyBy value, every time this loops it will store the result of the subsequent operation in different variable names (e.g anagramToTest1,2,3,4 etc...)

Code:

void multiplyNumber(int userInput)

while(multiplyBy<9)
{
	int multiplyBy = 2;
	userInput*multiplyBy = anagramToTest1;
	multiplyBy++;

}

You could create an array and change your loop a bit:

Code:

int anagramsToTest[7];
int i;

for(i = 0;i < 7;++i)
{
  multiplyBy = i + 2;
  ...
}

i would obviously become an index into the anagramsToTest array.

Your original loop had a bug in it that would cause the same anagram calculation every time. You had a multiplyBy variable that seemingly masked another multiplyBy variable, and that new variable was set to 2 on every iteration of the loop and then used in the calculation. Of course, you also had the lvalue on the right hand side of the assignment operator so you would have gotten a compile error anyway.