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.

In C++, when defining a class template, the "template" keyword is used. This keyword precedes the class definition and indicates to the compiler that it's a template definition. When creating an instance of the class template, you'll provide specific types for the template parameters, but the definition itself begins with "template".

In C++, when a for loop does not specify initialization, condition, and increment, it becomes an infinite loop. This means it will keep running indefinitely unless an external factor (like a break statement) interrupts its execution.

In C++, parentheses have the highest precedence among the listed options. They can be used to group operations and force a desired order of evaluation. This is a fundamental concept in most programming languages to control the order in which expressions are evaluated.

When passing by reference in C++, no additional memory is allocated. Instead, a reference serves as an alias to the original variable. It simply refers to the memory location of the original variable and doesn't create a separate copy of it. This contrasts with pass by value, where a copy of the object is made, which might lead to additional memory consumption.

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 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.

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.

The friendship in C++ is one-way. If class A declares class B or a function as its friend, it doesn't mean that class A automatically becomes a friend of class B or that function. Friendship must be explicitly granted. This means the granting of friendship is not reciprocal by default. Class B or the function would need to separately declare class A as a friend for the reverse to be true.

When a function has a default argument, it can be called with fewer arguments than it defines. The compiler will use the default value for any arguments not provided by the caller. This feature aids in providing flexibility while calling functions but doesn't directly enhance runtime performance.