Short Circuit Logical Operators
When the result can be determined by evaluating the preceding Logical expression without evaluating the further operands, it is known as short-circuiting.
Short-circuiting can be seen in the equation having more than one Logical operator. They can either AND, OR, or both.
1. Short Circuiting in Logical AND Operator
The logical AND operator returns true if and only if all operands evaluate to true. If the first operand is false, then the further operands will not be evaluated. This is because even if the further operands evaluate to true, the entire condition will still return false.
Example
C++
// C++ Program to illustrate short circuiting in Logical AND#include <iostream>using namespace std;// utility function to check positivebool is_positive(int number){ if (number > 0) return true; else return false;}// utility function to check if the number is evenbool is_even(int number){ if (number % 2 == 0) return true; else return false;}// driver codeint main(){ int x = 10; // Both conditions are evaluated if (is_positive(x) && is_even(x)) { cout << "Both conditions are satisfied." << endl; } else { cout << "Conditions not satisfied." << endl; } int y = -5; // The first condition is evaluated and found to be // false, so the second condition is not evaluated if (is_positive(y) && is_even(y)) { cout << "Both conditions are satisfied." << endl; } else { cout << "Conditions not satisfied." << endl; } return 0;} |
Both conditions are satisfied. Conditions not satisfied.
2. Short Circuiting in Logical OR Operator
OR operator returns true if at least one operand evaluates to true. If the first operand is true, then the further operands will not be evaluated. This is because even if the further operands evaluate to false, the entire condition will still return true.
Example
C++
// C++ program to illustrate the short circuiting in Logical// OR#include <iostream>using namespace std;// utility function to check positive numberbool is_positive(int number){ if (number > 0) return true; else return false;}// utility function to check if the number is evenbool is_even(int number){ if (number % 2 == 0) return true; else return false;}// driver codeint main(){ int x = 8; // The first condition is evaluated and found to be // true, so the second condition is not evaluated if (is_positive(x) || is_even(x)) { cout << "At least one condition is satisfied." << endl; } else { cout << "Conditions not satisfied." << endl; } int y = -5; // The first condition is evaluated and found to be // false, so the second condition is evaluated if (is_positive(y) || is_even(y)) { cout << "At least one condition is satisfied." << endl; } else { cout << "Conditions not satisfied." << endl; } return 0;} |
At least one condition is satisfied. Conditions not satisfied.
C Logical Operators
Logical operators in C are used to combine multiple conditions/constraints. Logical Operators returns either 0 or 1, it depends on whether the expression result is true or false. In C programming for decision-making, we use logical operators.
We have 3 logical operators in the C language:
- Logical AND ( && )
- Logical OR ( || )
- Logical NOT ( ! )