How can you access the last element of a C++ STL vector named "myVector"?
- myVector.end()
- myVector.last()
- myVector.back()
- myVector[myVector.size()]
The member function back() provides direct access to the last element in a vector. On the other hand, myVector.end() returns an iterator pointing to the position after the last element, and myVector[myVector.size()] would result in undefined behavior since it tries to access out-of-bounds memory. There's no last() function in vector.
You’re maintaining a legacy C++ codebase which has limited comments and documentation. You encounter an erratic bug that only appears in the optimized build. What strategy might be most effective in isolating and fixing the bug?
- Add extensive documentation first
- Compare optimized and unoptimized assembly
- Refactor the entire codebase
- Use printf debugging
Comparing the optimized and unoptimized assembly can provide insights into how the compiler is altering the code, potentially revealing the source of the erratic behavior. It's a meticulous process but can be effective for bugs that only manifest in optimized builds due to compiler transformations.
What is a potential risk of using recursion?
- Always faster than loops.
- Cannot handle large input data.
- Guarantees better readability.
- Uses less memory than loops.
One of the potential risks of using recursion is that it can lead to excessive memory use, especially when dealing with large input data. Every recursive call adds a new layer to the system's call stack, which can eventually result in a stack overflow if unchecked.
When performing a bitwise AND operation with a number and 0, the result is always _______.
- positive
- zero
- negative
- unchanged
When any number is bitwise AND-ed with 0, the result is always 0. This is because the AND operation yields 1 only if both bits being compared are 1; otherwise, it yields 0.
What is the output of the logical NOT (!) operator when applied to a non-zero operand?
- 0
- 1
- Undefined
- None
In C++, any non-zero value is considered as true. The logical NOT (!) operator inverts the truthiness of its operand. So, if applied to a non-zero (true) operand, the output will be false, which is represented as 0.
Unlike if-else, switch-case in C++ does not support _______ type for case values.
- floating-point
- integer
- character
- boolean
In C++, switch-case constructs don't support floating-point types for case values. This means you can't use float or double values as cases. On the other hand, if-else structures can easily handle conditions based on floating-point values.
Which of the following scenarios is the most suitable for applying recursion?
- Iterating through elements in an array.
- Calculating the total sales of a company.
- Solving problems that have repetitive structures.
- Creating graphical user interfaces.
Recursion is particularly suitable for problems that exhibit repetitive or nested structures. Examples include problems like calculating factorial, traversing trees, or solving the Towers of Hanoi. Such problems can be broken down into smaller instances of the same problem, making them perfect candidates for a recursive approach.
What is the primary purpose of a function in C++ programming?
- To print outputs
- To define variables
- To store data
- To perform a specific task
Functions in C++ allow code to be modularized, providing a way to encapsulate and reuse code. Their primary role is to perform a specific task or computation, ensuring the code is organized, clear, and maintainable.
When a float is converted to an int, the value is _______.
- truncated
- rounded
- incremented
- exponentiated
When a floating-point number is converted to an integer in C++, any fractional part is discarded (i.e., truncated). This does not involve rounding, just a simple removal of the decimal and beyond.
In professional C++ coding, it is often recommended to avoid using break and continue in favor of _______.
- structured logic
- recursive functions
- exception handling
- inline functions
While break and continue have their uses, over-reliance on them can make code harder to read and debug. Instead, it's often recommended to use clear and structured logic that doesn't rely on abrupt jumps within loops.