Read a text file and Loop through each letter or number in the line

[jinila21]

Hello, I just started learning to program and i need some help. I've tried searching but I don’t understand any of the answers.
So I’m given a .txt file that looks like this
E123456675786897907987867567467
F4545465876897980980
J54564676987979890879786756456455634
..................................................................
I'm asked to make C++ code to
-Open the text file
-Loop through the lines
-Loop through each letter or number in the line (i.e., read it as a string)
-Open an excel sheet
-Output the results to the excel sheet
I can get C++ to read the file & output the file in excel sheet; but I don’t get how to Loop through each letter or number in the line (i.e., read it as a string); if that’s even possible. Anyways, if someone could help me with an answer that would really help. Thanks.

[crazzyguy101]

but I don’t get how to Loop through each letter or number in the line (i.e., read it as a string); if that’s even possible.

What do you mean ? You can only read a std::string or char[] from a file. The numbers, by default would be read as std::string or char[].

[Galik]

Here is a loop:

#include <iostream>
#include <fstream>

std::ifstream ifs("my-data.txt");

std::string line;

while(std::getline(ifs, line))
{
    // do whatever you want with the line here
}

[jinila21]

I have done this loop but it is not working. it just reads only one line of the text file and then it stops.

while(std::getline(ifs, line))
{
int i=0;
intReturn = atoi(line.c_str());
word=line.substr(i,intReturn);
i=i+intReturn;
}
Please help.

[crazzyguy101]

intReturn = atoi(line.c_str());

Do you need to that ? You only got to put it in an excel file. So, why do you need to convert it to number ? Try putting all numbers in a string array as strings.

[Galik]

I have done this loop but it is not working. it just reads only one line of the text file and then it stops.

I think you may be causing a SEGFAULT with your substr() call.

The question says this:

Question wrote:

-Loop through each letter or number in the line (i.e., read it as a string)

You can do that like this:

for(int i = 0; i < line.length(); ++i)
{
    char ch = line[i]; // select one letter/number at a time from string line.

    // do whatever you like with your letter/number stored in ch.
}

[jinila21]

Actually i want to read lines from a text file.then write each line in a row and each character in a column of csv file. the text file has 600 lines. Bellow i am giving some of that lines

W39000779310701010008085018904037037064114044012044
W39000779310701010008089017204038037061112035012038
W39000779710701010009087022905047042057013055097033012037
W39000779310701010008097004304010030008144014035011
W39000779310701010008101002504011035010059002009002
W39000779310701010005097007702030068047
in my code its only take the first line and then stop working. please help me on this.

Thanks

[Galik]

I have already given you working answers to your questions. I'm not going to write the program for you.

[jinila21]

you are not getting my point. i have done what you have suggested, but still it is running only for one line. then it says error occurred while running the program.
What do I do now?

[crazzyguy101]

Why dont you just post the line that causes the error ?

[Galik]

Yes, please post the code exactly as you have it now so we can check what you have done and see what might be causing it.