warning C4244: 'argument' : conversion from 'time_t' to 'unsigned int', possible loss of data — C++

Question

I made a simple program that allows the user to pick a number of dice then guess the outcome... I posted this code before but with the wrong question so it was deleted... no

Answer 1

This line involves an implicit cast from time_t which time returns to unsigned int which srand takes:

srand ( time(NULL) );

You can make it an explicit cast instead:

srand ( static_cast<unsigned int>(time(NULL)) );

Answer 2

time() returns a time_t, which can be 32 or 64 bits. srand() takes an unsigned int, which is 32 bits. To be fair, you probably won't care since it's only being used as a seed for randomization.

Answer 3

That's because on your system, time_t is a larger integer type than unsigned int.

• time() returns a time_t which is probably a 64-bit integer.
• srand() wants an unsigned int which is probably a 32-bit integer.

Hence you get the warning. You can silence it with a cast:

srand ( (unsigned int)time(NULL) );

In this case, the downcast (and potential data loss) doesn't matter since you're only using it to seed the RNG.

Answer 4

This line involves an implicit cast from time_t which time returns to unsigned int which srand takes:

srand ( time(NULL) );

You can make it an explicit cast instead:

srand ( static_cast<unsigned int>(time(NULL)) );