Brownian Bridge™

1. A function receives `const double* weights` and `int n`. Inside the function, which of the following is a compile error?

`double w = weights[2];``const double* p = weights + 1;``weights[0] = 1.0;``int len = n;`

2. Consider this code snippet: ```cpp double* get_rate() { double r = 0.05; return &r; } ``` What is the fundamental problem with this function?

It should return `const double*` instead of `double*`It returns a pointer to a local variable; the variable is destroyed when the function returns, leaving a dangling pointerIt compiles only in C++20, not C++17`double` variables cannot be declared inside functions

3. What is the output of the following code? ```cpp int n = 5; double* p = new double[n](); p[0] = 1.0; p[1] = 2.0; delete p; ```

The code is well-formed and prints nothing; the array is freed correctlyUndefined behaviour: `delete` must be `delete[]` for heap arrays; using `delete` on an array allocation is UBCompile error: `new double[n]` requires a constant expression for `n`The code leaks only `p[2]` through `p[4]`; `p[0]` and `p[1]` are correctly freed

4. When a C-style array `double v[10]` is passed to a function declared as `void f(double* p)`, the function can determine the number of elements in `v` using `sizeof(p) / sizeof(double)`.

truefalse

5. In C++, what is the key performance advantage of allocating a `double path[252]` on the stack rather than via `new double[252]`?

Stack memory is in a faster CPU cache tier than heap memoryStack allocation is a single stack-pointer adjustment (O(1), no allocator overhead, no syscall); heap allocation involves the allocator's bookkeeping and may require an OS page requestStack arrays use 32-bit floats internally, halving memory bandwidthThe compiler always vectorises stack arrays but not heap arrays

6. The following function is correct and safe: ```cpp void add_position(double& portfolio_value, const double price, const double quantity) { portfolio_value += price * quantity; } ``` Calling it as `add_position(pv, 105.0, 100.0)` modifies `pv` in the caller.

truefalse

Quiz: C Language Foundations

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