$*22\mathrm{.}3($Pattern matching$)$ Write an $O(n)$ time program that prompts the user to enter two strings and tests whether the second string is a substring of the first string. Suppose the neighboring characters in the string are distinct. $($Don$\text{'}$t use the indexOf method in the String class.$)$

Sample Run for Exercise$22\_03.$java

Enter input data for the program $($Sample data provided below. You may modify it$.)$

Welcome to Java

come

Show the Sample Output Using the Preceeding Input

Execution Result:

JDK$8>$java Exercise$22\_03$

Enter a string s$1$: Welcome to Java

Enter a string s$2$: come

matched at index $3$

JDK$8>$