Question

hi, please help in c++.

I dont understand how to do this, and a lot of the ways on the internet is confusing me, i am a beginner.

with all steps and explantions, will rate!

Write a program that determines the frequency of each char in an input file. Your program should . read in an unknown number of chars from an input file named input.txt, • using a function written by you, determine the frequency of occurrence of each char in the list • write each char followed by the frequency to the output file output.txt. • The chars should appear in the output file in the same order as they first appeared in the input file. First draw a flow chart and then attempt the code. Example 1 Example input and output files can be seen in Listings 9 and 10. Listing 9: Example of input.txt Page 4 of 5 Listing 10: Example of output.txt

Answer 1

Ans)

this is counting using ascii encoding from 'a'-'z' i.e 26 charctors are their

assuming alphabet[0] is counting for 'a' likewise others a[25] counting for 'z'

in below function we are reducing current char i.e str[i] - 'a' it will give the

difference between 'a' and given char which is equal to char in array

for example :

assume current chars is c then, 'c'-'a' =2 in ascii and in alphabet[2] will be incremented

alphabet[0] counting for a alphabet[1] for b and alphabet[2] for c

this is way its working

Code:

#include <iostream>

#include <string>

#include <fstream>

using namespace std;

int count[26];                        // to store frequency of every alphabet

char* toCharArray(string out){           //to convert output string to char array

    char* array;

    array = new char[out.size() + 1];

    for (int i = 0; i < out.size(); i++)

    {

        array[i] = out[i];

    }

    return array;

}

int main() {        // main function

    string filename,outfile;

    cout << "Enter File name:";

    cin >> filename;

    cout << "Enter Full name and path of outfile:";

    cin >> outfile;

    ifstream file;

    file.open((filename.c_str()));            //if file does not exist   

    if (!file)

    {

        cout << "Cannot Open file";

        return 0;

    }

    string out,temp;

    out = "";

    while (!file.eof())             //reading all charctors from file

        {

            getline(file,temp);

            out.append(temp);

          

        }

    file.close();

    char *str = toCharArray(out);

//please read this for better understanding   

/*

this is counting using ascii encoding from a-z 26 charctors are their

assuming alphabet[0] is counting for 'a' likewise others a[25] counting for 'z'

in below function we are reducing current char i.e str[i] - 'a' it will give the

difference between 'a' and given char which is equal to char in array

for example :

assume current chars is c then, 'c'-'a' =2 in ascii and in alphabet[2] will be incremented

alphabet[0] counting for a alphabet[1] for b and alphabet[2] for c

this is way its working

*/

    int i = 0, alphabet[26] = {0}, j;

    while (str[i] != '\0') {                       //counting frequency of every alphabet

        if (str[i] >= 'a' && str[i] <= 'z') {

            j = str[i] - 'a';

            ++alphabet[j];

        }

        ++i;

    }

    ofstream output;

    output.open(outfile.c_str());           //opening output file

    for (i = 0; i < 26; i++)                

    {

        if (alphabet[i] == 0)           //we are skipping char whose count is zero

        {                               //we will not put them into file    

            continue;

        }

        output << char(i + 'a') << " " << alphabet[i] << "\n";

   }

    return 0;

}