class stringPatten{

//You are required to make a simple JAVA program to ask the user for a character string,

//test whether it contains a substring a*b or not, and print it

private int f = 0, l = 0;

String str1 = new String();

public boolean interpret(String str){

str1 = str;

int len = str1.length() - 1;

char[] char1 = str1.toCharArray();

int i = 0, count = 0;

boolean bool = true;

while ((i <= len) & bool)

{

char aa = char1[i++];

if (( aa == 'b') || (aa == 'B')){

l = i;

int j = i - 2;

while ((j >= 0) & (char1[j] == 'a' || char1[j] == 'A')){

j--;

}

f = j + 1;

bool = false;

}

}

return bool;

}

public int getf(){

return f;

}

public int getl(){

return l;

}

}


public class Main{

public static void main(String[] arg) {

String str1 = new String();

stringPatten strP = new stringPatten();

boolean bool = true;

try

{

str1 = arg[0];

} catch (ArrayIndexOutOfBoundsException e)

{

System.out.println(" Sorry for the incorrect input, following the input as ");

System.out.println(" java Main InputString ");

return;

}

//method interpret to judge whether the given string satisfies the patten of a*b or not

bool = strP.interpret(str1);

if (bool == false)

System.out.println(" This string has a patten of a*b " + str1.substring(strP.getf(), strP.getl()) );

else

System.out.println(" This string doesn't satisfy a patten of a*b " );

}

}