Operator precedence - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of mixed arithmetic and bitwise operators

What is the output of this C code snippet?

C

int main() {
    int a = 5, b = 3, c = 2;
    int result = a + b << c;
    printf("%d", result);
    return 0;
}

A 14

B 16

C 32

D 13

💡 Hint

Remember that bitwise shift operators have lower precedence than addition.

The expression is evaluated as (a + b) << c = (5 + 3) << 2 = 8 << 2 = 32, since + has higher precedence than <<. The output is 32.

❓ Predict Output

intermediate

Output of logical and bitwise operators combined

What is the output of this C code?

C

int main() {
    int x = 1, y = 0;
    int z = x && y & x;
    printf("%d", z);
    return 0;
}

A 0

B 1

C 2

D 3

💡 Hint

Check operator precedence between && and & operators.

The & operator has higher precedence than &&, so y & x is evaluated first: 0 & 1 = 0. Then x && 0 is evaluated: 1 && 0 = 0. So the output is 0.

❓ Predict Output

advanced

Result of complex expression with mixed operators

What is the output of this C program?

C

int main() {
    int a = 4, b = 2, c = 3;
    int result = a - b * c / b + c;
    printf("%d", result);
    return 0;
}

A 4

B 7

C 3

D 9

💡 Hint

Remember multiplication and division have higher precedence than addition and subtraction.

First, b * c / b = (2 * 3) / 2 = 6 / 2 = 3 (left-to-right). Then a - 3 + c = 4 - 3 + 3 = 4 (left-to-right for - and +). The output is 4.

❓ Predict Output

advanced

Output of expression with ternary and logical operators

What does this C code print?

C

int main() {
    int x = 0, y = 5;
    int z = x ? y : y > 3 ? 10 : 20;
    printf("%d", z);
    return 0;
}

A 5

B 10

C 20

D 0

💡 Hint

Ternary operators associate right to left. Evaluate carefully.

Since x is 0 (false), the expression evaluates the second ternary: y > 3 ? 10 : 20. y is 5, which is greater than 3, so the result is 10.

❓ Predict Output

expert

Value of variable after complex expression with increments and precedence

What is the value of variable x after running this C code?

C

int main() {
    int x = 3;
    int y = x++ * ++x + x-- - --x;
    printf("%d", x);
    return 0;
}

A 2

B 1

C 4

D 3

💡 Hint

Remember the order of evaluation and side effects of post and pre increments.

This expression has undefined behavior due to multiple modifications to x without sequence points. Assuming left-to-right operand evaluation (common in many compilers): - x++: uses 3, x=4 - ++x: x=5, uses 5 - x++ * ++x = 3*5=15 - x--: uses 5, x=4 - --x: x=3, uses 3 - 15 + 5 - 3 = 17 (y=17) Final x=3, prints 3.