i'm confused about forward functions and integrating them in my loop
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i'm writing a program to find the prime digital root, which is when you add all the indiv. #s of an integer until you reach a single digit number OR when you reach a prime number
2^31 = (2147483648) = 2+1+4+7+4+8+3+6+4+8 = (47) = 4+7 = (11) = 1+1 = (2)
the prime digital root is 47 because 47 is prime... but assuming 47 and 11 aren't prime, it would stop at 2 because it is a single digit number and that would be the prime digital root
right now, my forward functions are countNumbers(counts the numbers) --> digitSum(adds the digits of an integer) --> primeChecker(checks if digitSum is prime) and then after that i'd just have to add one that checks whether it is a single digit or not
i am confused about a few things:
1.) what if i only want to run countNumbers() in my forward function to count the number of digits in the integer to put in my while loop in main. how would i do that?
2.) how would i incorporate my forward functions into my while loop so that the program (not finished) actually adds the digits of an integer, checks if it's prime, checks if it's a single digit or not and then goes back to the sum of the digits of the integer and starts the process all over again?
thanks!
Code:
/*@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ @
@ Forward Function Declarations @
@ @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@*/
int countNumbers(unsigned int N)
unsigned int digitSum(unsigned int N, unsigned int numberLength);
unsigned int primeChecker(unsigned int digitSum);
/*@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@
The main function
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@*/
int main(void)
{
unsigned int N, numberLength, duplicateN, digitSum, digitSumDuplicate, i, sum[max_array_length];
int isPrime;
FILE *input, *output;
numberLength = 1; //initialize numberLength at 1
isPrime = 0; //we assume number is not prime until proven by primeChecker()
i = 0; //initialize first value in array sum[] to be 0
if ((input = fopen("prime_root.dat", "r")) == NULL)
{
printf("Error: cannot read the file prime_root.dat\n");
return 1;
}
if ((output = fopen("prime_root.out", "w")) == NULL)
{
printf("Error: cannot write to the file prime_root.out\n");
fclose(input);
return 1;
}
while()
{
fscanf(input, "%d\n", &N);
while(N != 0)
{
if (numberLength > 1)
return 0;
}
/*@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ @
@ Function Definitions @
@ @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@*/
/************************************************** ****************************
*
* Function countNumbers()
*
************************************************** *****************************
*
* This function takes an integer N as input, counts how many
* individual numbers it consists of and returns the number.
*
************************************************** ****************************/
int countNumbers(unsigned int N)
{
duplicateN = N;
while(duplicateN >= 10)
{
duplicateN = duplicateN / 10;
numberLength++;
}
return numberLength;
}
/************************************************** ****************************
*
* Function digitSum()
*
************************************************** *****************************
*
* This function takes integers N and numberLength as input and ,
* length of the integer, respectively, and adds the digits of the
* input and returns the result
************************************************** ****************************/
unsigned int digitSum(unsigned int N, unsigned int numberLength)
{
for(numberLength > 0)
{
sum[i] = N % 10;
N = N / 10;
i++;
numberLength--;
}
for(i > 0)
{
digitSum += sum[i-1];
i--;
}
return digitSum;
}
/************************************************** ****************************
*
* Function primeChecker()
*
************************************************** *****************************
*
* This function takes integer digitSum and checks if it is the prime
* number and then returns isPrime either 0 for no or 1 for yes.
*
************************************************** ****************************/
unsigned int primeChecker(unsigned int digitSum)
{
for(digitSumDuplicate = digitSum; digitSumDuplicate > 1; digitSumDuplicate--)
{
if(digitSum % digitSumDuplicate == 0)
{
isPrime = 1;
}
else
{
N = digitSum;
}
}
return isPrime;
}
----->>>>>
:P :P
