/********************* raw2latex.c *******************
 *                                                   *
 * Solution of Problem 4 of Homework Group 1.        *
 * Problem: (in Hungarian)                           *
 * http://www.phy.bme.hu/~balogh/szamszim2011/#03het *
 *                                                   *
 *****************************************************
 * L\'aszl\'o Balogh, blaci947@yahoo.co.uk           *
 * Sep 20 2011                                       *
 *****************************************************/

// buffer size for 1 line of input (10k should be enough)
#define  MAXLINE  10000

#include <stdio.h>
#include <math.h>

char* double2str(double d_, char* str_);

int main(void){
  int    a;                    // 1st field in the input file
  double b, c;                 // 2nd and 3rd field in the input file
  char   bstr[100], cstr[100]; // the scientific notation of b and c
  char   line[MAXLINE];        // temporary storage for 1 line of input

  // This code fragment was reused from the class.
  // SRC: http://www.phy.bme.hu/~balogh/szamszim2011/src/1/pow.c
  
  // read the first line from the input:
  fgets(line, MAXLINE, stdin);
  // process until the end of the input file:
  while (!feof(stdin)) {
    if ( sscanf(line, "%d %lf %lf", &a, &b, &c) == 3 ) {
      double2str(b, bstr);
      double2str(c, cstr);
      fprintf(stdout, "  %4d  &  %s  &  %s  &  %6.2lf  \\\\\n", a, bstr, cstr, 1.0E-6*c/b);
    }
    else { // the line contains something else:
      fprintf(stdout, "%s", line);
    }
    // read the next line from the input:
    fgets(line, MAXLINE, stdin);
  }
  fclose(stdout);
  return 0;
}

char* double2str(double d_, char* str_) {
  // converts the real number d_, to scientific notation in LaTeX format
  // e.g., 3.14E0 --> $3.14\cdot 10^{0}
  // stores the result in str_ (NOTE: it must be large enough)
  // the return value is str_
  
  double exponent;
  double coefficient;
  
  // the exponent is the log_10 of the (absolut value of the) number:
  exponent = log10(fabs(d_));
  
  // if the number is 0 (or -0) we do not use the scientific notation:
  // for the explanation of HUGE_VAL see:
  //   http://www.cplusplus.com/reference/clibrary/cmath/log10/
  if ( exponent == -HUGE_VAL ) {
    sprintf(str_, "$%2.0f$", d_);
    return str_;
  }
  
  // the exponent in the scientific notation should be integral:
  exponent = floor(exponent);
  
  // calculate the coefficient, using the exponent
  coefficient = d_ * pow(10.0, -exponent);
  
  // store the result:
  sprintf(str_, "$%5.2lf\\cdot 10^{%d}$", coefficient, (int)exponent);
  
  return str_;
}