Arrays and Strings - Beginning Java - page 180

int endIndex = 0; // Substring end

index
for(int i = 0; i < count; ++i) {
endIndex = text.indexOf(separator,index); // Find next
separator

if(endIndex == -1) { // If it is not found

subStr[i] = text.substring(index); // extract to the end

} else { // otherwise

subStr[i] = text.substring(index, endIndex); // to end index

}

index = endIndex + 1; // Set start for

next cycle
}

// Display the substrings
for(String s : subStr) { // For each string

in subStr
System.out.println(s); // display it

}

}

ExtractSubstrings.java

When you run this example, you should get the following output:
To
be
or
not
to
be

How It Works
After setting up the string text to be segmented into substrings, a count variable to hold the number of
substrings, and the separator character, separator , the program has three distinct phases:
1. The first phase counts the number of substrings by using the indexOf() method to find separators.
The number of separators is always one less than the number of substrings. By using the do-while
loop, you ensure that the value of count is one more than the number of separators because there is
always one loop iteration for when the separator is not found.
2. The second phase extracts the substrings in sequence from the beginning of the string and stores
them in an array of String variables that has count elements. A separator follows each substring from
the first to the penultimate so you use the version of the substring() method that accepts two index
arguments for these. The last substring is signaled by a failure to find the separator character when
endIndex is −1. In this case you use the substring() method with a single argument to extract the
substring through to the end of the string text .