Write a program to count number of lines from a text files that ends at ‘.’

Question

#include<iostream.h>
 #include<fstream.h>
int main()
{
    ifstream infile("text.txt");
    char ch[50];
    int count=0,i;
    for(i=0;infile.eof()==0;i++)
    {
        infile.getline(ch,50);
        if(ch[i]=='\n')
            if(ch[i-1]=='.')
                count++;
    }
    cout<<"Total number of lines are:"<<count;
}

I tried this code but it doesnt seem to work.I used the logic to take all the file contents in ch and then subsequently check for newline character and '.'
How do I make it work.
Please help?

EDIT new code

#include<iostream.h>
#include<fstream.h>
int main()
{
    ifstream infile("text.txt");
    char ch[50];
    int count=0,i;
    while(!infile.eof())
    {

        infile.getline(ch,50);
        for(i=1;ch[i]!='\n';i++);
        if(ch[i-1]=='.')
                count++;    

    }
    cout<<"Total number of lines are:"<<count;
}

add some debugging to your loop to look at what you read in, your index variable etc... — Nim, Jun 14 '16 at 09:01
don't guess, try to understand what is happening with that variable, and what `getline()` is doing... — Nim, Jun 14 '16 at 09:03
You're checking wrong. variable `i` in this case counts the number of lines you've read, yet you use it to access the index inside an array of chars. — DaMachk, Jun 14 '16 at 09:08
Please read [Why is iostream::eof inside a loop condition considered wrong?](http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong). — Some programmer dude, Jun 14 '16 at 09:10
As for your problem, learn about [`std::string`](http://en.cppreference.com/w/cpp/string/basic_string) and [`std::getline`](http://en.cppreference.com/w/cpp/string/basic_string/getline). — Some programmer dude, Jun 14 '16 at 09:12
also, `eof()` returns a boolean, don't compare it to a number, specially where a boolean is expected! — Garf365, Jun 14 '16 at 09:18
With new code, you don't care about some of comments : **don't use** `eof` in condition of `while` and don't compare boolean variable with an integer (just write `!infile.eof()` or `infile.eof() == false`) — Garf365, Jun 14 '16 at 09:30
Read [Why is iostream::eof inside a loop condition considered wrong?](http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong). — molbdnilo, Jun 14 '16 at 09:38
@user3500780 some advice still missing, see JoachimPileborg and molbdnilo comments about http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong — Garf365, Jun 14 '16 at 09:45
@molbdnilo I don't understand what is conveyed in the link :/ — user3500780, Jun 14 '16 at 09:47
Tagging the question as [tag:turboc++], since you are using a primordial 1980s dialect of the language. — Lightness Races in Orbit, Jun 14 '16 at 09:55
@LightnessRacesinOrbit tell me a thing tho, aren't almost all language same in structure and logic but different in keywords?? — user3500780, Jun 14 '16 at 14:13
@user3500780: Yes, extremely. Compare FORTRAN with Haskell with Java with Prolog with Brainfuck with etc etc Perhaps you're only considering imperative and OO-like languages, many of which are superficially similar at least. — Lightness Races in Orbit, Jun 14 '16 at 15:42

SHR · Answer 1 · 2016-06-14T21:06:55.367

0

you have problem with long lines
you have problem with '\r' on windows
you are not looking properly at the end of line.
in the last line you may not have '\n'

check out this solution:

#include <stdlib.h>
#include<iostream>
#include<fstream>
#include<string>
using namespace std;
int main()
{
    ifstream infile("text.txt");
    string str;
    int count=0;
    while(std::getline(infile,str))
    {
        string::reverse_iterator it=str.rbegin();
        while(it != str.rend() && iswspace(*it)) it++;
        if(*it =='.') count++;
    }
    cout<<"Total number of lines are:"<<count;
    return 0;
}

edited Jun 14 '16 at 21:06

answered Jun 14 '16 at 09:22

SHR

7,940
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There is no problem with newlines on Windows since the file is opened in text mode. – molbdnilo Jun 14 '16 at 09:26
I tried this program and it counts all the lines whether or not ending with '.' – user3500780 Jun 14 '16 at 09:35
@user3500780 it fixed. – SHR Jun 14 '16 at 21:07

score 0 · Answer 2 · answered Jun 14 '16 at 09:36

Your program is undefined if any line is longer than fifty characters (the original version is undefined if the file is longer), your end-of-file test is wrong, and the last line doesn't necessarily end with a newline.

You might write it something like this.

int main()
{
    ifstream infile("text.txt");
    std::string line;
    int count = 0;
    while (infile.getline(line))
    {
        if (line.back() == '.')
        {
            count += 1;
        }
    }
    cout << "Total number of lines are:" << count;
}

score 0 · Answer 3 · answered Jun 14 '16 at 09:48

Since you have mentioned 50 as maximum line size. I tried to write a code based on that assumption

int main()
{
    ifstream infile("text.txt");
    char str[50]; int strSize = 50;
    int count = 0;

    while (infile.getline(str, strSize, '.')) {
        count++;
    }

    cout << "Total number of lines are:" << count << endl;

    infile.close();
    return 0;
}

This code basically counts the number of lines based on number of '.' present in a line, whether a sentence is in a new line or not.

Write a program to count number of lines from a text files that ends at ‘.’

3 Answers3