Remove Duplicate Characters from Strings in an Array

[apendris140]

I am trying to remove the duplicate characters from strings in an array. The strings were read from a file. I had it output the array and that part I am successful on. After writing the function i received the error "error: cannot convert 'std::__cxx11::string {aka std::__cxx11::basic_string<char>}' to 'char*' for argument '1' to 'void removeRepeats(char*, int)'removeRepeats (strings1[i], rows);" I tried changing the types around only to receive more errors. I changed the types back to the original in the code below.

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

void removeRepeats (char strings1[], int rows);

int main()
{
    char string_file[20];    
    cout << "What is the name of the file?\n";
    cin >> string_file;

    ifstream in_stream(string_file);
    if (!in_stream)
    {
        cout << "file not open: " << string_file << '\n';
        return 1; 
    }
    
    const int rows  = 20;
    string strings1[rows];
    
    int i = 0;
    while (i<rows && getline(in_stream, strings1[i])) 
    {
        i++;
    }
    
    for (int n=0; n<i; ++n)
        removeRepeats (strings1[i],  rows);
        cout << strings1[i] << '\n';
    
    in_stream.close();
}

void removeRepeats (char strings1[], int rows)
    {
         for (int i=0; i <rows; i++)
           {
                 char c=strings1[i];
               for(int j=i+1; j <rows; j++)
                  {
                     if(c==strings1[j])
                       strings1 [j]=' ';
                   }
             }
      }

[JayhawkZombie]

Try making your function look like this:

void RemoveRepeats(std::string &strings1, int rows)
{
  ...
  for (int j = i + 1; j < rows; j++)
  {
    if (c == strings1[j])
      strings1[j] = ' ';
  }
  ...
}

Pass the string by reference so that you modify the original string and not a copy of the string.

[apendris140]

I'm still receiving the same error message after making the changes.

[integralfx]

string strings1[rows];

void removeRepeats (char strings1[], int rows)

char string_file[20];
Consider using std::string, so to allow the user to enter an arbitrary length filename.

const int rows  = 20;
string strings1[rows];

Similarly, I'd recommend you to use a std::vector here.

[boost lexical cast]

Removing duplicate characters from a string.

#include <iostream>
#include <string>

int main()
{
    std::string str = "aaabbbccc";
    const std::string::size_type size = str.size();
    std::cout << str << "\n\n\n";
    std::string chars;

    unsigned short int index = 0;

    for (char c : str)
    {
        if (chars.find(c) != std::string::npos)
        {
            str.erase(str.begin() + index);
            str.resize(size);
        }
        else
        {
            chars.push_back(c);
        }
        ++index;
    }

    str.shrink_to_fit();

    std::cout << str << '\n';

    std::cin.get();

    return 0;
}