Explicit Assignment vs Implicit Assignment

I'm reading a tutorial for C++ but it didn't actually give me a difference (besides syntax) between the two. Here is a quote from the tutorial.

You can also assign values to your variables upon declaration. When we assign values to a variable using the assignment operator (equals sign), it’s called an explicit assignment:

int nValue = 5; // explicit assignment

You can also assign values to variables using an implicit assignment:

int nValue(5); // implicit assignment

Even though implicit assignments look a lot like function calls, the compiler keeps track of which names are variables and which are functions so that they can be resolved properly.

Is there a difference? Is one more preferred over the other?