C++ functions to detect and shift pitch of audio sample array

This project is the creation of a C++ file that I can include in a larger project. There are two functions that I will need to call. The first is a pitch detection function and the second is a pitch shifting function. The pitch detection function should take, as an argument, an array of audio samples. The samples sent to the function will be between -1.0 and 1.0. The function should return the primary frequency of the signal in hertz. Ideally, the function will be able to detect the pitch given an audio sample array of 64 samples. If the function requires a greater number of samples, that is acceptable, but it should be a multiple of 64. The pitch shifting function should take as arguments 1) an array of audio samples, and 2) a float representing the factor to shift the pitch of the sample array. Ideally, the function will be able to shift the pitch of a sample array of 64 samples. If the function requires a greater number of samples, that is acceptable, but should be a multiple of 64. As to the second argument, the float is the frequency scaling factor. For example, passing 1.0 should return the audio at normal speed. Passing an argument of 0.5 lowers pitch one octave. Passing an argument of 2.0 raises audio one octave. No external libraries or third-party code may be used or relied upon in the final delivered product. If you see technical insufficiencies or oversights in my spec, feel free to propose and explain any changes. To bid on this project, you must include you proposed deadline for delivery. Additionally, providing any links or examples of previous work in the audio programming field will be very favorably considered.