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Logical Operators in if...else Conditions

Logical operators are used within if conditions to combine multiple expressions. They allow you to create more complex and precise conditions for decision-making.

Key Topics

1. Understanding Logical Operators

Operator Symbol Description
Logical AND&&True if both operands are true
Logical OR||True if at least one operand is true
Logical NOT!Inverts the truth value of the operand

2. Examples of Logical Operators in Conditions

Example: Checking Age and Citizenship

#include <stdio.h>
#include <stdbool.h>

int main() {
    int age = 20;
    bool isCitizen = true;
    if (age >= 18 && isCitizen) {
        printf("Eligible to vote.\n");
    } else {
        printf("Not eligible to vote.\n");
    }
    return 0;
}

Example: Validating Input Range

#include <stdio.h>

int main() {
    int num = 15;
    if (num >= 10 || num <= 20) {
        printf("Number is within the acceptable range.\n");
    } else {
        printf("Number is outside the acceptable range.\n");
    }
    return 0;
}

3. Operator Precedence

Logical operators have specific precedence levels:

  • ! (Logical NOT) has higher precedence than && and ||.
  • && (Logical AND) has higher precedence than || (Logical OR).

Use parentheses () to group conditions and make the order of evaluation explicit.

Best Practices

  • Use logical operators to simplify multiple conditions.
  • Use parentheses to clarify complex conditions and ensure correct evaluation.
  • Be cautious of short-circuit evaluation, where the second operand may not be evaluated.

Don'ts

  • Don't assume the order of evaluation without parentheses.
  • Don't make conditions overly complex; consider breaking them into simpler parts.
  • Don't forget that logical operators return integer values (0 or 1).

Key Takeaways

  • Logical operators enhance the flexibility of conditions in if...else statements.
  • Understanding operator precedence is crucial for writing correct conditions.
  • Clear and well-structured conditions improve code readability and maintainability.
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