Returning a character in an array of strings

[Red265]

\\I begin with opening a file, declaring an array of strings, and placing the \\individual lines in the file into arrays of strings.

string line[1000]; \\the number 1000 is an arbatrary expected
\\maximum number of lines in the file
int i=0;
while(getline(infile1, line[i], '\n'))
{
i++;
}

\\ The array is size i

Now I would like to read each string in this array while searching for a particular character and then return the number (of the string in the array) that the character occured at.


Any suggestions as to how to go about this would be greatly appreciated.

[Ganon11]

Well, you will need two loops. The first will iterate through the array of strings. The second will check each character in the string to see if it matches your character. What would the limits of these loops be?

[Red265]

Well, you will need two loops. The first will iterate through the array of strings. The second will check each character in the string to see if it matches your character. What would the limits of these loops be?

Sorry, I don't know if I was entirely clear in my post. What I am trying to do is find the line number in a file that a particular character occurs at.

My strategy was to begin by reading all of the lines in the file into an array of strings, with each string representing an individual line within the file.

What I don't know how to do, and consequently, what I need to do next is read each string (individually) while looking for the character, stopping when the character is found at some line in the array. This line could be represented as line[j], for example with (int j) representing the string (line in the file) the character was found at) and then returning the j value.

As far as boundaries, any decently large number that would represent a maximum number of characters expected in a line of a text file would do.
200 would more than suffice for this purpose.

If there is an easier way to go about this I'm open to suggestions.

Thanks

[Ganon11]

My suggestion still stands - you need to loop through the array of strings and through each character in the array. This time, however, as soon as you find the correct character, you can return the 1st index - this will be the line index where the character was found.

[Red265]

Thanks for your input, Gannon. Here is my attempt at what you suggested
It compiles without error, but it doesn't output anything because my loops
must be a botched. Any suggestions on how to fix them are welcome.

// Some code has been removed.
// line is an array of strings - i is the arrays size.
 
char t='a';     // character I'm looking for the first occurrence of
 
int n;            // will represent individual string (line) lengths
 
for (int j=0; j<i; j++) // counter loop for sorting through strings
   {
   n=line[j].length();   // finds length of individual strings
 
   char ch[n];        // declares array of characters
 
   line[j]=ch[n];      // sets array of characters equal to the string at that instance
 
   int k;                 // counter variable
 
   for (k=0; k<=n; k++)  // loop for counting characters in the char array
    {
        if ( ch[k] == t )  // if this character is the character I'm looking for
           {
       break;           // don't look anymore
 
                         cout << "Character "
        << t
          << " was found on line "
        << j
        << " on position "
        << k
        << " within the line. "
        << endl;
                    }
    }
   }
 
return 0;
}

[weaknessforcats]

Use the find_if() algorithm

[Ganon11]

The main problem you have is that you write

line[j] = ch[n];

This sets the jth element of line (a string) to the nth character of ch (a character). This will rewrite whatever information you had stored in line. Also, ch[n] is accessing a single character - should you be setting it equal to a sequence of characters (i.e. char array)? Finally, ch[n] is out of bounds - ch has elements at ch[0], ch[1], ch[2],..., ch[n-1].

You should probably write

ch = line[j].c_str();

or instead of this, just use

line[j][k];

in place of

ch[k];

[Red265]

Gannon, I don't think this does anything but rename the character.

ch = line[j].c_str();

And wouldn't something like this only work if all the columns were the same in each row?

line[j][k];

All I'm trying to do is figure out line and position number in a text file.

[Ganon11]

Gannon, I don't think this does anything but rename the character.

ch = line[j].c_str();

Not sure what you mean - as long as ch was declared as a char*, this should make ch the cstring representing line[j].

And wouldn't something like this only work if all the columns were the same in each row?

line[j][k];

The first operation done will be line[j]. This will return a string object. Then the [k] resolves. std::string has overloaded the bracket operation to access the character in the kth position, so line[j][k] will work. Instead of looping to n, though, you will have to loop until line[j].length(), ensuring that you don't go out of bounds.