C Logical Operators in Conditions

🔗 C Logical Operators in Conditions (Beginner → Advanced)

In C language, logical operators are used to combine or modify conditions.
They are most commonly used in if statements, loops, and conditional expressions.

1️⃣ What Are Logical Operators?

Logical operators work with conditions (true/false) and return either 1 (true) or 0 (false).

C has three logical operators:

2️⃣ Logical AND (&&) ⭐

Rule

✔ Result is true only if all conditions are true

Example

✔ Both conditions must be satisfied

3️⃣ Logical OR (||) ⭐

Rule

✔ Result is true if any one condition is true

Example

✔ Only one condition is enough

4️⃣ Logical NOT (!) ⭐

Rule

✔ Reverses the result of a condition

Example

✔ !0 → 1 (true)
✔ !1 → 0 (false)

5️⃣ Using Logical Operators in if-else

✔ Common in grading systems

6️⃣ Logical Operators with while Loop ⭐

✔ Loop runs only while condition is true

7️⃣ Logical Operators with for Loop

✔ Stops when i == 7

8️⃣ Truth Table (Very Important for Interviews) ⭐

AND (&&)

OR (||)

NOT (!)

9️⃣ Short-Circuit Evaluation ⭐ (Very Important)

AND (&&)

✔ Second condition executes only if first is true

OR (||)

✔ Second condition executes only if first is false

📌 Prevents runtime errors (like divide by zero)

🔟 Logical vs Bitwise Operators ⚠️

❌ Do NOT confuse them

1️⃣1️⃣ Common Mistakes ❌

❌ Using & instead of &&
❌ Using | instead of ||
❌ Forgetting parentheses
❌ Assuming non-zero means only 1

✔ Any non-zero value is true

📌 Interview Questions (Must Prepare)

1. Difference between && and &

2. What is short-circuit evaluation?

3. Output of if (5 && 10)?

4. Difference between logical and bitwise operators

5. When || skips second condition?

🔥 Real-Life Use Cases

• Login validation (username && password)

• Range checking

• Menu conditions

• Input validation

• Loop control

✅ Summary

✔ Logical operators combine conditions
✔ && → all true
✔ || → any true
✔ ! → reverse condition
✔ Short-circuit improves safety
✔ Essential for conditions, loops & interviews