What will be the output?

string result $=""$;

string input $="261835"$;

int i $=0$;

do $\{$

$$switch $($input$[$i$])\{$

$$ case $\text{'}1\text{'}$:

$$ result $+="$a$"$;

$$ break;

$$ case $\text{'}2\text{'}$:

$$ result $+="$b$"$;

$$ break;

$$ case $\text{'}3\text{'}$:

$$ result $+="$c$"$;

$$ break;

$$ case $\text{'}4\text{'}$:

$$ result $+="$d$"$;

$$ case $\text{'}5\text{'}$:

$$ result $+="$e$"$;

$$ result $+="$f$"$;

$$ case $\text{'}0\text{'}$:

$$ break;

$$ default:

$$ result $+="$x$"$;

$\}$

$$ i$++$;

$\}$while $($input$[$i$]!=\text{'}\backslash 0\text{'})$;

$$cout $<<$result $<<$endl;