Boolean Data Type
Boolean (bool
) is a data type that can take one of two values: true
or false
. Syntax:
bool
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bool alive = true;
1bool alive = true;
They are mostly used in comparison operators. Those operators (==
, !=
, <
, >
, >=
, <=
) return bool
.
Note
std::cout
prints booleans as numbers,1
if the boolean istrue
, and0
if the boolean isfalse
.
main
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#include <iostream>
int main()
{
bool istrue = true;
bool obv = (5 > 0);
bool wrong = (2 * 2 == 5);
std::cout << istrue << std::endl;
std::cout << obv << std::endl;
std::cout << wrong << std::endl;
}
123456789101112#include <iostream> int main() { bool istrue = true; bool obv = (5 > 0); bool wrong = (2 * 2 == 5); std::cout << istrue << std::endl; std::cout << obv << std::endl; std::cout << wrong << std::endl; }
You can also flip the value of a boolean using the !
operator:
main
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#include <iostream>
int main()
{
bool istrue = true;
std::cout << istrue << std::endl;
std::cout << !istrue << std::endl;
}
123456789#include <iostream> int main() { bool istrue = true; std::cout << istrue << std::endl; std::cout << !istrue << std::endl; }
And most frequently, they are used as conditions in if
/while
/... statements.
main
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#include <iostream>
int main()
{
bool b = true;
if (b)
std::cout << "b is true" << std::endl;
if (1 > 0)
std::cout << "1 is greater than 0" << std::endl;
}
123456789101112#include <iostream> int main() { bool b = true; if (b) std::cout << "b is true" << std::endl; if (1 > 0) std::cout << "1 is greater than 0" << std::endl; }
The size of a bool
is 1 byte. Yes, it would fit in 1 bit of memory, but you can't store a variable of size less than 1 byte (8 bit).
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