Hello

I commented some parts of the code to make it clearer what the C code is trying to do.

#define N 100

int len = floor(10 * N/3) + 1;

// define an array, in C the size must be specified during compile
// time (just use @a and let the loop populate the array with <len>
// elements)
int A[len];
for(int i = 0; i < len; ++i) {
  A[i] = 2;
}

int nines    = 0;
int predigit = 0;

for(int j = 1; j < N + 1; ++j) {
  // iterate over the reversed array, transform each value
  // and calculate q -> 'map {...} reverse @a' ?
  int q = 0;
  for(int i = len; i > 0; --i) {       
    int x  = 10 * A[i-1] + q*i;        
    A[i-1] = x % (2*i - 1);            
    q = x / (2*i - 1);
  }

  A[0] = q%10;
  q  = q/10;
  if (9 == q) {
    ++nines;
  }
  else if (10 == q) {
    printf("%d", predigit + 1);

    // print '0'x$nines;
    for (int k = 0; k < nines; ++k) {     
      printf("%d", 0);
    }

    predigit, nines = 0;
  }
  else {
    printf("%d", predigit);
    predigit = q;
    if (0 != nines) {

      // print '9'x$nines;
      for (int k = 0; k < nines; ++k) {   
        printf("%d", 9);
      }

      nines = 0;
    }
  }
}

printf("%d", predigit);

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In reply to Re: porting C code to Perl by Monk::Thomas
in thread porting C code to Perl by Discipulus

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