$3.($Using loop and conditional statements together operating on character variables$)$

Write a C program that converts the phone number having numbers$/$letters into one having numbers only.

$-$ Allow the user to enter a phone number. It can contain numbers, letters, and symbols $($see sample inputs below$).$

$-$ The program will output any number elements.

$-$ The program will also echo a hyphen in addition to numbers.

$-$ The program will output $\text{'}?\text{'}$ for non$-$number elements.

$-$ You will use "while" loop structure where looping is required.

Ex: If the input is: $\backslash (1-555-\backslash )$ HOLIDAY

The output will be: Numbers only: $1-555-????????$

If the input is: $\backslash (1-555\backslash )-$holiday

The output will be: Numbers only: $1-555-????????$

If the input is: $999-9999$

The output will be: Numbers only: $999-9999$

If the input is: $\backslash (9876\backslash$mathrm$\{$zywx$\}\backslash \%\backslash$$ $\backslash$# $\backslash )$

The output will be: Numbers only: $9876????$