Course Content
C++ Introduction
C++ Introduction
Relational Operators
Relational operators (>
, <
, >=
, <=
, ==
, !=
) are used to compare two values. They determine the relationship between the values and and give true
or false
.
To output true
when printing a boolean value with std::cout
, you can simply use std::cout
with a bool value.
main
#include <iostream> int main() { std::cout << true; }
By default, std::cout
prints one for true
and zero for false
. To print true
and false
as words, you need to use the std::boolalpha
manipulator. It instructs std::cout
to display boolean values as words instead of numbers.
first_boolaplha_usage
second_boolaplha_usage
#include <iostream> int main() { std::cout << std::boolalpha << true; }
Using operators
To compare whether something is equal, use the ==
operator with two equal signs. Remember, =
is a different operator used for assignment, not comparison.
main
#include <iostream> int main() { // Imagine you need to verify if the user has entered the correct password std::cout << std::boolalpha; std::cout << ("yw>r'Peq/2d" == "yw>r'Peq/2d") << std::endl; std::cout << ("yw>r'Peq/2d" == "VzF>.6Qy(UI?") << std::endl; }
When using the >
(greater than) and <
(less than) relational operators, you can compare two values to check which one is larger or smaller. The result will be true
if the condition holds, and false
otherwise.
main
#include <iostream> int main() { std::cout << std::boolalpha; // Checking if a customer has enough balance // To withdraw 300 from an account balance of 500 std::cout << (500 > 300) << std::endl; }
If the user wants to withdraw 500 and their balance is also 500, the >
operator will return false
, as it checks if the balance is strictly greater than the withdrawal amount. However, the withdrawal is still possible. In this case, you should use the >=
or <=
operator to check if the balance is greater than or equal to the withdrawal amount, which would correctly return true
.
main
#include <iostream> int main() { std::cout << std::boolalpha; // Checking if a customer has enough balance // To withdraw 500 from an account balance of 500 std::cout << (500 >= 500) << std::endl; }
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