How do the concepts of synchrony and parallelism differ in programming?

Synchronous and parallel are different concepts in programming:

• Synchronous means that operations are performed sequentially: the next operation starts only after the previous one is completed. For example, if a function calls another synchronously, it will wait for the result before continuing.

• Parallel means that multiple operations can be performed simultaneously, for example, on different CPU cores or threads. This allows increasing performance by executing tasks concurrently.

Example:

// Synchronous call
void Process()
{
    var result = LongRunningOperation(); // wait for completion
    Console.WriteLine(result);
}

// Parallel call using tasks
async Task ProcessAsync()
{
    var task = LongRunningOperationAsync();
    // Other actions can be performed in parallel
    var result = await task; // wait for asynchronous completion
    Console.WriteLine(result);
}

Thus, synchrony is about the order of execution, and parallelism is about simultaneous execution.