arrange line in txt file in ASCII order using array and display them

Question

#include <stdio.h>
#include <string.h>
#include <fstream>
#include <iostream>

using namespace std;

int main() {
    ifstream infile;          // ifstream is reading file
    infile.open("read.txt");  // read.txt is the file we need to read
    std::cout << infile;
    string str;
    if (infile.is_open()) {
        while (getline(infile, str)) {
            char str[2000], ch;
            int i, j, len;
            len = strlen(str);
            for (i = 0; i < len; i++) {
                for (j = 0; j < (len - 1); j++) {
                    if (str[j] > str[j + 1]) {
                        ch = str[j];
                        str[j] = str[j + 1];
                        str[j + 1] = ch;
                    }
                }
            }
        }
        cout << "\nProcessed data:" << str;
    }

    return 0;
}

My txt file:

Today is a fine day.
It’s sunny.
Let us go out now!

My result should be:

    .Taaaddefiinosyy
 ’.Innsstuy
    !Legnooosttuuw

Spaces is consider here as well. I'm new to C++. I need some pros help. Thank you very much!

Answer 1

Your code does not work, because:

1. The line std::cout << infile; is wrong. If you want to print the result of istream::operator bool() in order to determine whether the file was successfully opened, then you should write std::cout << infile.operator bool(); or std::cout << static_cast<bool>(infile); instead. However, it would probably be better to simply write std::cout << infile.fail(); or std::cout << !infile.fail();.
2. The function std::strlen requires as a parameter a pointer to a valid string. Maybe you intended to write str.length()? In that case, you should delete the declaration char str[2000], because it shadows the declaration string str;.
3. You should print the sorted result immediately after sorting it, before it gets overwritten by the next line. Currently you are only printing the content str a single time at the end of your program, so you are only printing the last line.

After performing the fixes mentioned above, your code should look like this:

#include <stdio.h>
#include <string.h>
#include <fstream>
#include <iostream>

using namespace std;

int main() {
    ifstream infile;          // ifstream is reading file
    infile.open("read.txt");  // read.txt is the file we need to read
    std::cout << infile.fail();
    string str;
    if (infile.is_open()) {
        while (getline(infile, str)) {
            char ch;
            int i, j, len;
            len = str.length();
            for (i = 0; i < len; i++) {
                for (j = 0; j < (len - 1); j++) {
                    if (str[j] > str[j + 1]) {
                        ch = str[j];
                        str[j] = str[j + 1];
                        str[j + 1] = ch;
                    }
                }
            }

            cout << "\nProcessed data:" << str;
        }
    }

    return 0;
}

For the input

Today is a fine day.
It's sunny.
Let us go out now!

this program has the following output:

0
Processed data:    .Taaaddefiinosyy
Processed data: '.Innsstuy
Processed data:    !Legnooosttuuw

Note that the input posted in your question contains a forward tick ’ instead of an apostrophe '. This could cause trouble. For example, when I tested your program, this forward tick was encoded into a multi-byte UTF-8 character, because it is not representable in 7-bit US-ASCII. This caused your sorting algorithm to fail, because it only supports single-byte characters. I was only able to fix this bug by replacing the forward tick with an apostrophe in the input.