Question

I have written a program in C running on UNIX which counts the number of each letters in a input text file. For a file like this:

‘The cat sat on the green mat’

The output would be like this:

   The letter ’a’ occurs 3 times.
   The letter ’c’ occurs 1 times.
   The letter ’e’ occurs 4 times.
   The letter ’g’ occurs 1 times.
   The letter ’h’ occurs 2 times.
   The letter ’m’ occurs 1 times.
   The letter ’n’ occurs 2 times.
   The letter ’o’ occurs 1 times.
   The letter ’r’ occurs 1 times.
   The letter ’s’ occurs 1 times.
   The letter ’t’ occurs 5 times.

  5                    *
  4     *              *
  4     *              *
  3 *   *              *
  3 *   *              *
  2 *   *  *     *     *
  2 *   *  *     *     *
  1 * * * **    ***  ***
  1 * * * **    ***  ***
  0 **************************
  0 **************************
... abcdefghijklmnopqrstuvwxyz

Where the graph represents the amount of times a letter appears. (If it is more than 10, i simply put a ‘+’ after the 10th row). The code I’ve currently written to achieve this is as follows:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

void drawGraph(int letters[26], char alpha[26]);
void printLetters(int letters[26], char alpha[26]);
void getLetters(FILE *fp, int letters[26], char alpha[26]);

int main(int argc, char *argv[]) {
  FILE *fp;
  int letters[26] = { 0 };
  char alpha[26] = { 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z' };
  int indexedAlpha[256] = { 0 };
  int j = 1;

  for (i = 97; i <= 127; i++)
    {
      indexedAlpha[i] = j;
      j++;
    }

  //open file
  if ((fp = fopen(argv[1], "r")) == NULL)
    {
      perror("Cannot open file");
      exit(EXIT_FAILURE);
    }

  getLetters(fp, letters, alpha);
  printLetters(letters, alpha);
  printf("\n");
  drawGraph(letters, alpha);
  printf("\n");

  return EXIT_SUCCESS;
}

void getLetters(FILE *fp, int letters[26], char alpha[26]) {
  int c;
  for (int i = 0; (c = fgetc(fp)) != EOF; i++)
    {
      c = fgetc(fp);
      if ( isalpha(c) )
    {
      for ( int j = 0; j < 26; j++ ) //find which letter it is
        {
          if( c == alpha[j] ) 
        {
          letters[j]++;
          break;
        }
        }
    }
    }
}

void printLetters(int letters[26], char alpha[26]) {
  for( int i = 0; i < 26; i++ )
    {
      if(letters[i] != 0){
    printf("The letter '%c' occurs %d times.\n", alpha[i], letters[i]);
      }
    }
}

void drawGraph(int letters[26], char alpha[26]) {
  int x = 11;
  int y;
  while(x >= 0)
    { 
      y = 0;
      while (y < 2)
    {
      if (x == 10)
        {
          printf(" %d ", x);
        }
      else if (x == 11)
        {
          printf("    ");
        }
      else
        {
          printf("  %d ", x);
        }

      for( int i = 0; i < 26; i++ )
        {
          if(letters[i] > 10)
        {
          printf("+");
          letters[i] = 10;
          y++; // Break out of while loop
        }
          else if(letters[i] == x)
        {
          printf("*");
        }
          else
        {
          printf(" ");
        }
          if (letters[i] == x && y == 1)
        {
          letters[i] = letters[i] - 1;
        }
        }
      printf("\n");
      y++;
    }
      x--;
    }
  printf("... ");

  for( int i = 0; i < 26; i++ )
    {
      printf("%c", alpha[i]);
    }
}

However my current code has two problems.
1. I always print out 10 Y-axis points i want to only print out as many Y-axis points as needed, What would be the best way to achieve this?
2. Currently only lower case characters are counted, how can i address this?

Also any notation or better methodology would be much appreciated, Im still trying to learn!

Thanks!

Answer 1

2nd question seems bit easy to me :

2. Currently only lower case characters are counted, how can i address this?

make an structure like this :

    typedef struct 
    {
     char c; 
     int count;
    }alpha;

    alpha abc[26];

for(i=0 ; i<26 ; i++)
  abc[i].count = 0; // Initialization of count for each alphabet
for(i=0;i<26; i++)
  abc[i].c = 'a' + i;

In this way you can keep track of each letter with it’s count.

To print “histogram” of each alphabet in file you need (11 + 1 + 1) lines

(means at least 13 lines , can be extra lines for separating characters and their bar )

11 lines for 11 times occurrence of alphabet and 1 for + as mentioned and 1 for alphabets itself.

But to print these lines, You need to take care of extra things about the space before the each of the *(histogram symbol you used).

So, loop through the array and print it like, For your 1st question try something like this:

int cnt;
for(cnt = 11 ; c >=0 ; c--)
{
 for(i=0; i<26; i++)
 {
  if(abc[i].count >= cnt && cnt == 11)  
  {
   space = abc[i].c - 'a';
   printf("%*c",space,'+'); // setting indentation and printing
  }
  if(abc[i].count == cnt && cnt != 11)  
  {
   space = abc[i].c - 'a';
   printf("%*c",space,'*');  //// setting indentation and printing
  }
  printf("\n");
 } //end of inner for loop
} // end of outer for loop 

printf("abcdefghijklmnopqrstuvwxyz\n");