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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4.  
  5. int euclid_gcd(int a, int b) {
  6.   if (b == 0) return a;
  7.   return euclid_gcd(b, a % b);
  8. }
  9.  
  10. void reducesimple(char *buf,
  11.                   int integer,
  12.                   const char *floating)
  13. {
  14.   int flen = strlen(floating);
  15.   int scale = 1;
  16.   int gcd;
  17.   int decimal;
  18.   while (flen--) scale *= 10;
  19.   decimal = atoi(floating);
  20.   gcd = euclid_gcd(decimal, scale);
  21.   sprintf(buf, "%d + %d/%d", integer, decimal / gcd, scale / gcd);
  22. }
  23.  
  24. void reducerational(char *buf,
  25.                     int numerator,
  26.                     int denominator)
  27. {
  28.   int whole = numerator / denominator;
  29.   int rest = numerator % denominator;
  30.   int gcd = euclid_gcd(rest, denominator);
  31.   if (!whole) {
  32.     sprintf(buf, "%d/%d", rest / gcd, denominator / gcd);
  33.   } else {
  34.     sprintf(buf, "%d + %d/%d", whole, rest / gcd, denominator / gcd);
  35.   }
  36. }
  37.  
  38. void reducerepeating(char *buf,
  39.                      int integer,
  40.                      const char *floating,
  41.                      const char *repeating)
  42. {
  43.   int flen, rlen;
  44.   int num = 1, den = 1;
  45.   int gcd;
  46.   int fscale = 1, rscale = 9;
  47.   int part1, part2;
  48.  
  49.   part1 = atoi(floating);
  50.   part2 = atoi(repeating);
  51.  
  52.   rlen = strlen(repeating);
  53.   while (--rlen) { rscale *= 10; rscale += 9; }
  54.   flen = strlen(floating);
  55.   while (flen--) rscale *= 10;
  56.   flen = strlen(floating);
  57.   while (flen--) fscale *= 10;
  58.  
  59.   num = part1 * rscale + fscale * part2;
  60.   den = fscale * rscale;
  61.   gcd = euclid_gcd(num, den);
  62.   sprintf(buf, "%d + %d / %d", integer, num / gcd, den / gcd);
  63. }
  64.  
  65. void reduce(char *buf, const char *expression) {
  66.   int chk1, chk2, chk3, chk4;
  67.   int integer, numerator, denominator;
  68.   char floating[11], repeating[11];
  69.  
  70.   chk1 = sscanf(expression, "%d.%10[0123456789]", &integer, floating);
  71.   chk2 = sscanf(expression, "%d/%d", &numerator, &denominator);
  72.   chk3 = sscanf(expression, "%d.%10[0123456789](%10[0123456789])", &integer, floating, repeating);
  73.   chk4 = sscanf(expression, "%d.(%10[0123456789])", &integer, repeating);
  74.   if ((chk3 == 3) || (chk4 == 2)) {
  75.     if (chk4 == 2) *floating = 0;
  76.     reducerepeating(buf, integer, floating, repeating);
  77.   } else {
  78.     if (chk2 == 2) {
  79.       reducerational(buf, numerator, denominator);
  80.     } else {
  81.       if (chk1 == 2) {
  82.         reducesimple(buf, integer, floating);
  83.       } else {
  84.         strcpy(buf, "invalid expression");
  85.       }
  86.     }
  87.   }
  88. }
  89.  
  90. int main(void) {
  91.   char buf[1000], src[1000];
  92.   while (fgets(src, sizeof src, stdin)) {
  93.     src[strlen(src) - 1] = 0;
  94.     reduce(buf, src);
  95.     printf("%s ==> %s\n", src, buf);
  96.   }
  97.   return 0;
  98. }
Success #stdin #stdout 0.01s 1724KB
comments (?)
stdin
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0.333333333
0.333
0.(3)
0.1(6)
10/8
3.(012)
3.4(042)
3.00(4)
3.00(42)
stdout
copy 
0.333333333 ==> 0 + 333333333/1000000000
0.333 ==> 0 + 333/1000
0.(3) ==> 0 + 1 / 3
0.1(6) ==> 0 + 1 / 6
10/8 ==> 1 + 1/4
3.(012) ==> 3 + 4 / 333
3.4(042) ==> 3 + 673 / 1665
3.00(4) ==> 3 + 1 / 225
3.00(42) ==> 3 + 7 / 1650
https://ideone.com/ngZrS
language:
C99 (gcc 8.3)
created:
12 years ago
visibility:
secret

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