The use of XOR for removing character from string and finding duplicates

The following questions are based on the use of XOR :

Given a string say of integers. The task at hand is to remove the given character from string. I tried using XOR to solve it. eg char str[] = "123456" . Remove 4. XOR the given character with the entire string. That character vanishes.
```
XOR = (1^2^3^4^5^6) ^ 4
```
However I am left with the XOR of the remaining characters.
```
XOR = (1^2^3^5^6)
```
Is there any method I could get the individual characters back?
I need to find and remove elements that have duplicates (including the elements themselves)

eg. A = {1,9,8,2,2} then output should be {1,9,8} after removal

However this will fail since 1^9 = 8. Hence (1^9)^8^2^2 gives empty array. Is there any alternative using XOR itself?

Solution

int num=4;
for(i=0;i<strlen(str);i++)
{
    if(((str[i]-'0')^num) == 0)
        remove_number(i);
}