Question

Checking the limits of the type long long using

std::cout << std::numeric_limits<long long>::min();

I get -9223372036854775808

However when compiling the following code:

int main() {
   long long l;
   l=-9223372036854775808LL;
}

I get the warnings:

test.cpp:3:7: warning: integer constant is so large that it is unsigned.
test.cpp:3: warning: this decimal constant is unsigned only in ISO C90

What am I missing?
Many thanks in advance for your help.

Giorgio

Answer 1

This 9223372036854775808LL is a positive number. So you need to take

std::cout << std::numeric_limits<long long>::max();

into consideration. Negating it immediately afterwards doesn’t make the operand of the - operator itself negative.