Question

C program:

Write a program that assigns and counts the number of each alphabetic character in the Declaration of Independence and sorts the counts from the most used to the least used character.

• Consider upper and lower case letters the same.
• The frequency of each character should be accumulated in an array.
• USE POINTERS to increment counts for each letter, sort your array, and display the results.
• Output should consist of two columns: (1) each letter 'a'-'z' and (2) the frequency with which each letter occurs.

Submitting the Assignment

You should submit the following:

• Your C source code.
• A Word document that contains your program and a screen shot of your results..  

Grading will be based upon the following:

• Program logic. Program produces results indicated in the problem statements. This includes
  • Use of an array to calculate frequencies.
  • Use of pointers to increment counts for each letter, sort the array to list characters from most to least, and display the results.
• Program syntax. The C language is used correctly.(10 points).
• Program appearance and formatting. White space and indentation are consistent with text examples. (10 points).
• Program documentation. Comments are consistent with text examples. (5 points).

Answer 1

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

int main()
{
char c,str[100];
int i,t,j=0, len;
int *freq,*f;
char al[26];
//allocate memory for storing the frequencies
freq = (int *)malloc(26 * sizeof(int));
f = (int *)malloc(26 * sizeof(int));

/* Input string from user */
printf("Enter any string: ");
gets(str);
//find the length of the entered string
len = strlen(str);

// Initialize frequency of each character to 0
for(i=0; i<26; i++)
{
*(freq+i) = 0;
}

// Find total number of occurrences of each character
for(i=0; i<len; i++)
{
// If the current character is lowercase alphabet
if(str[i]>='a' && str[i]<='z')
{
*(freq + (str[i]-97))= *(freq + (str[i]-97))+1;
          
}
else if(str[i]>='A' && str[i]<='Z') // if the character is uppercase character
{
   *(freq + (str[i]-65))= *(freq + (str[i]-65)) +1;
  
}
}

for(i=0; i<26; i++)
{
// If current character exists in given string
if(*(freq+i) != 0)
{
al[j]=(char)(i+97); //assignthe character to al
*(f+j)=*(freq+i); //assign the frequencies to f
j++;
       }
}
free(freq); //delete the freq array from meory
len=j; //assign the total number of alphabet types to len
//sort the frequescies in descending order
for(i=0;i<len;i++)
for(j=0;j<len;j++)
{
   if(*(f+i)>*(f+j))
   {
      t=*(f+i); //swap the frequencies
      *(f+i)=*(f+j);
      *(f+j)=t;
     
      c=al[i]; //swap the characters
      al[i]=al[j];
      al[j]=c;
           }
       }
       /* Print the frequency of all characters in the string */
   printf("\nFrequency of all characters in the given string: \n");
   for(i=0;i<len;i++)  
printf("\n%c %d",al[i],*(f+i));

free(f); //deallocate f

return 0;
}

output