All Flashcards
Why use loops with strings?
To iterate through characters and substrings.
Explain string indexing.
Accessing characters by their position in the string.
What is the core idea of string reversal?
Building a new string by prepending characters.
How does a 'sliding window' work?
It extracts all substrings of a given length by moving one character at a time.
Why is equals() preferred over == for strings?
equals() compares content; == compares references.
Why is tracing important?
Helps visualize the process and catch errors early.
What is the importance of boundary conditions?
Ensuring algorithms work correctly at the start and end of strings.
What is the role of immutability in string manipulation?
Requires creating new strings for modifications.
Why is string searching important?
Fundamental in text processing and pattern recognition.
What is the time complexity of basic string operations?
Varies, but often O(n) for operations like searching or reversal.
What does the following code output?
java
String s = "abc";
System.out.println(s.substring(1, 3));
bc
Identify the error in the following code:
java
String s = "hello";
for (int i = 0; i <= s.length(); i++) {
System.out.println(s.charAt(i));
}
IndexOutOfBoundsException: Loop should be i < s.length().
What does the following code output?
java
String s1 = "hello";
String s2 = new String("hello");
System.out.println(s1.equals(s2));
true
What does the following code output?
java
String s = "world";
String result = "";
for (int i = 0; i < s.length(); i++) {
result = result + s.charAt(i);
}
System.out.println(result);
world
Identify the error in the following code:
java
String s = "test";
System.out.println(s.substring(2, 1));
StringIndexOutOfBoundsException: endIndex cannot be less than beginIndex.
What does the following code output?
java
String s = "apple";
System.out.println(s.length());
5
What does the following code output?
java
String s = "OpenAI";
System.out.println(s.substring(4));
AI
Identify the error in the following code:
java
String s = null;
System.out.println(s.length());
NullPointerException: Cannot call length() on a null string.
What does the following code output?
java
String s1 = "hello";
String s2 = "Hello";
System.out.println(s1.equals(s2));
false
What does the following code output?
java
String s = "programming";
System.out.println(s.indexOf("gram"));
3
What is a string?
A sequence of characters.
What is substring()?
A method that returns a portion of a string.
What does equals() do?
Compares two strings for content equality.
What is an index in a string?
The position of a character in the string, starting from 0.
Define 'string reversal'.
Creating a new string with characters in reverse order.
What is a 'sliding window'?
A technique to process substrings of a fixed size.
Define 'substring'.
A contiguous sequence of characters within a string.
What is string immutability?
The property that strings cannot be changed after creation.
What is the purpose of length()?
Returns the number of characters in a string.
What is string concatenation?
Joining two or more strings end-to-end.