$*3.$ Operators such as $,$ which read input from the keyboard, must be able to convert a series of digits into a number. Write a program that does the same thing. It should allo the user to type up to six digits, and then display the resulting number as a type long integer. The digits should be read individually, as characters, using getche$().$ Constructing the number involves multiplying the existing value by $10$ and then adtit? the new digit. $($Hint: Subtract $48$ or $\text{'}0\text{'}$ to go from ASCII to a numerical digit.$)$