confused

This is a discussion on confused within the C Programming forums, part of the General Programming Boards category; can anyone explain what is happening in this program I really dont understand it. thank you. Code: #include <stdio.h> int ...

  1. #1
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    confused

    can anyone explain what is happening in this program I really dont understand it. thank you.

    Code:
    #include <stdio.h>
    
    int main() {
    
      int index, freq[26], c, stars, maxfreq;
    
      for (index=0; index<26; index++)
        freq[index] = 0;
    
      while ( (c = getchar()) !=EOF) {
    
        if (isalpha(c))
          freq[2*(tolower(c)-'a')]++;
      }
    
    
      maxfreq = freq[0];
      for (index = 1; index < 26; index++) {
    
        if (freq[index] > maxfreq)
          maxfreq = freq[index];
      }
    
      for (index=maxfreq; index>=1; index--) {
    
        for (stars=0; stars<26; stars++) {
    
          if (freq[stars] >= index)
            printf("*");
          else
            printf(" ");
        }
        printf("\n");
      }
      printf("abcdefghijklmnopqrstuvwxyz\n");
    system("pause");
      return 0;
    }

  2. #2
    C++ Witch laserlight's Avatar
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    Please be reminded of our homework policy.
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
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    please be reminded its not homework its a practice question for a test im preparing for.

  4. #4
    and the hat of copycat stevesmithx's Avatar
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    As you say it is not a HW,
    It is a pgm to print a Histogram based upon the frequency of alphabets in ur
    input.
    Not everything that can be counted counts, and not everything that counts can be counted
    - Albert Einstein.


    No programming language is perfect. There is not even a single best language; there are only languages well suited or perhaps poorly suited for particular purposes.
    - Herbert Mayer

  5. #5
    C++ Witch laserlight's Avatar
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    please be reminded its not homework its a practice question for a test im preparing for.
    That's homework.

    Attempt the question, give what you think is the answer.
    C + C++ Compiler: MinGW port of GCC
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  6. #6
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    as stevesmithx allready said it writes a '*' for every letter inputed, but it is flawed for it only accepts letters up to 'm' cuz of your
    Code:
    freq[2*(tolower(c)-'a')]++;
    and I don't think this was such a hard problem that you couldn't do on your own, but still, that's what it does.

    by

  7. #7
    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    but it is flawed for it only accepts letters up to 'm' cuz of your
    Actually, I'd call that a little more than a flaw... Entering "zzz" causes out of bounds array access in this program.
    long time; /* know C? */
    Unprecedented performance: Nothing ever ran this slow before.
    Any sufficiently advanced bug is indistinguishable from a feature.
    Real Programmers confuse Halloween and Christmas, because dec 25 == oct 31.
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    recursion (re - cur' - zhun) n. 1. (see recursion)

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