Rust中的无符号整数溢出

Question

I am a beginner to Rust. In the code:

println!("{}", 4400202385408u64 * 34359738368u64);

The rust compiler gives me the following error:

error: attempt to multiply with overflow 

despite the fact that the result of the multiplication is within std::u64::MAX

Can someone point me to what is happening?

Answer 1

despite the fact that the result of the multiplication is within std::u64::MAX

Pretty sure it's not.

Converting to hex, you're doing 0x40080800800 * 0x800000000. They're both individually well over a u32 MAX, so when you multiply them together they're well over a u64 max.