what is static assert in c++ code example

Example 1: c++ assert

assert(std::is_same_v<int, int>); // error: assert does not take two arguments
assert((std::is_same_v<int, int>)); // OK: one argument
static_assert(std::is_same_v<int, int>); // OK: not a macro
std::complex<double> c;
assert(c == std::complex<double>{0, 0}); // error
assert((c == std::complex<double>{0, 0})); // OK

Example 2: c++ assert

static_assert(sizeof(long) == 8, "long must be 8 bytes");
static_assert(sizeof(int) == 4, "int must be 4 bytes");
 
int main()
{
	return 0;
}