Duplicate removal characters

Duplicate removal characters
#include <iostream>
#include <cstring>
using namespace std;
int main()
{
    char str  [50];
    char strn [50];
    char ch,ch1 ;
    int i = 0;
    cout<<"Enter the string: ";
    cin>>str;
    int len = strlen(str);
    for( i=1 ; i<len;i++)
    {
        ch = str[i]


    }
    str[i] = '\0';
    cout<<"string = "<<strn;
    return 0;
}