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  1. #include <stdio.h>
  2. #include <math.h>
  3.  
  4. #define N 26
  5. static char *s = "asdfasdagsdfa";
  6.  
  7. int main() {
  8.   static int a[N];
  9.   int n, i;
  10.   double e, t;
  11.   char *p;
  12.   for (p = s, n = 0; *p; p++, n++)
  13.     a[*p - 'a']++;
  14.   e = 0.0;
  15.   for (i = 0; i < N; i++)
  16.     if (a[i]) {
  17.       t =  (double)a[i] / n;
  18.       e += -t * log(t) / log(2.0);
  19.     }
  20.   printf("entroy: %f bits\n", e);
  21.   return 0;
  22. }
  23. /* end */
  24.  
Success #stdin #stdout 0s 2248KB
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stdin
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Standard input is empty
stdout
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entroy: 2.199688 bits
https://ideone.com/3toYuB
language:
C (gcc 8.3)
created:
11 years ago
visibility:
public

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