Project 1: Compute the frequencies of characters in a given input file. (Ignore

Question

Project 1: Compute the frequencies of characters in a given input file.

(Ignore all tabs, spaces and line returns)

I. Input: a txt file (use argv[])

II. Output: a txt file (use argv[]) with the following format:

(Do not print any charactors that have zero count.)

   char1 # count

   char2 # count

   char3 # count

   char4 # count

III. Data structure:

   - charIn (char)

   - index

   - charCounts[256] a 1D array where 256 is max number of different ascii characters.

     - printAry  

VI. Algorithm for counting

step 0: - open input and output files

     - initialize charCounts array to zero.

step 1: charIn <- get the next character from inFile, one character at a time

step 2: index <- cast charIn to integer

step 3: charCounts[index]++

step 4: repeat step 1 to step 3 while infile is not empty

step 5: printArray

step 6: close all files

VII. Algorithm for printArray

step 1: index <--0

step 2: if charCounts[index] > 0

          symbol <-- cast index to charactor

          write symbol charCounts[index] per text line

step 3: index ++

step 4: repeat step 2 to step 3 while i < 256

Explanation / Answer

Eg: ./a.out /home/user/input.txt /home/user/output/txt

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

int main(int oc, char **argv)
{
int index = 0;
char charIn = 0;
int charCounts[256] = {0};
int i = 0; //for for-loop

FILE *inFile = NULL;
FILE *outFile = NULL;

printf("input file %s ", argv[1]);
printf("output file %s ", argv[2]);

//Read the input File
inFile = fopen(argv[1], "r");
if (inFile == NULL)
{
printf("file open problem ");
}
else
{
fseek(inFile, 0, SEEK_END);
long fSize = ftell(inFile);
fseek(inFile, 0, SEEK_SET);

//read the file in repeat mode to get fetch each characters
while((charIn =fgetc(inFile)) != EOF)
{
//cast character to integer and store in charCounts index
index = (int)charIn;
charCounts[index]++;
}
fclose(inFile);

//open the output file in write mode.. if not existing file then it creates too. "W"
outFile = fopen(argv[2], "w");
if (outFile != NULL)
{
for(i = 1;i <256;i++)
{
//ignoring the file right is character not occured even once
if (charCounts[i] != 0)
{
fprintf(outFile, "char%d # %d ", i, charCounts[i]);
}
}
fclose(outFile);
}
}

}

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