Switch vs if comparison - Practice Questions

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of switch with fall-through

What is the output of this C code snippet?

C

#include <stdio.h>

int main() {
    int x = 2;
    switch (x) {
        case 1:
            printf("One\n");
        case 2:
            printf("Two\n");
        case 3:
            printf("Three\n");
            break;
        default:
            printf("Default\n");
    }
    return 0;
}

A

One
Two
Three

B

Two
Three

C

Two

D

Default

💡 Hint

Remember that switch cases fall through unless you use break.

The switch starts at case 2, prints "Two", then falls through to case 3 and prints "Three", then breaks. Case 1 is skipped.

❓ Predict Output

intermediate

If-else equivalent output

What is the output of this if-else code?

C

#include <stdio.h>

int main() {
    int x = 3;
    if (x == 1) {
        printf("One\n");
    } else if (x == 2) {
        printf("Two\n");
    } else if (x == 3) {
        printf("Three\n");
    } else {
        printf("Default\n");
    }
    return 0;
}

A

One

B

Two

C

Three

D

Default

💡 Hint

Check which condition matches the value of x.

Since x is 3, the third else-if condition is true, so it prints "Three".

❓ Predict Output

advanced

Switch with non-constant case labels

What error does this code produce?

C

#include <stdio.h>

int main() {
    int a = 1;
    int b = 2;
    switch (a) {
        case b:
            printf("B\n");
            break;
        default:
            printf("Default\n");
    }
    return 0;
}

A Output: Default

B Runtime error: segmentation fault

C Output: B

D Compilation error: case label does not reduce to an integer constant

💡 Hint

Case labels must be constant expressions in C.

In C, case labels must be compile-time constants. Using variable 'b' causes a compilation error.

🧠 Conceptual

advanced

Difference in evaluation between switch and if

Which statement about switch and if is true in C?

A Switch evaluates the expression once and jumps to matching case; if evaluates conditions sequentially.

B Switch evaluates all cases before executing any code.

C If evaluates all conditions before executing the matching block.

D Switch can evaluate ranges like if conditions can.

💡 Hint

Think about how switch jumps directly to a case.

Switch evaluates the expression once and jumps directly to the matching case label. If-else evaluates conditions one by one until one is true.

❓ Predict Output

expert

Output of nested switch and if

What is the output of this code?

C

#include <stdio.h>

int main() {
    int x = 1, y = 2;
    switch (x) {
        case 1:
            if (y == 2) {
                printf("A\n");
                break;
            }
            printf("B\n");
            break;
        case 2:
            printf("C\n");
            break;
        default:
            printf("D\n");
    }
    return 0;
}

A

A

B

B

C

C

D

D

💡 Hint

Check the if condition inside case 1 and where the breaks are.

Inside case 1, y == 2 is true, so it prints "A" and breaks out of the switch. "B" is not printed.