Loop execution flow - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested for loops with break

What is the output of the following C code?

C

#include <stdio.h>

int main() {
    for (int i = 1; i <= 3; i++) {
        for (int j = 1; j <= 3; j++) {
            if (j == 2) {
                break;
            }
            printf("%d%d ", i, j);
        }
    }
    return 0;
}

A 11 12 21 22 31 32

B 11 21 31

C 11 12 13 21 22 23 31 32 33

D 12 22 32

💡 Hint

Remember that break exits the innermost loop immediately.

The inner loop prints values until j == 2, then breaks. So only j == 1 prints for each i. The output is 11 21 31 .

❓ Predict Output

intermediate

Output of while loop with continue

What is the output of this C program?

C

#include <stdio.h>

int main() {
    int i = 0;
    while (i < 5) {
        i++;
        if (i == 3) {
            continue;
        }
        printf("%d ", i);
    }
    return 0;
}

A 2 3 4 5

B 1 2 3 4 5

C 1 2 4

D 1 2 4 5

💡 Hint

Think about what continue does inside a loop.

When i == 3, continue skips the printf for that iteration. So 3 is not printed. The output is 1 2 4 5 .

❓ Predict Output

advanced

Output of for loop with multiple increments

What is the output of this C code?

C

#include <stdio.h>

int main() {
    for (int i = 0; i < 5; i++) {
        printf("%d ", i);
        i++;
    }
    return 0;
}

A 0 2 4

B 0 1 2 3 4

C 0 1 3

D 1 3 5

💡 Hint

Notice the extra i++ inside the loop body.

The loop increments i twice each iteration: once in the for statement and once inside the loop. So i takes values 0, 2, 4 and prints them.

❓ Predict Output

advanced

Output of do-while loop with break

What is the output of this C program?

C

#include <stdio.h>

int main() {
    int i = 0;
    do {
        if (i == 2) {
            break;
        }
        printf("%d ", i);
        i++;
    } while (i < 5);
    return 0;
}

A 0 1 2

B 0 1 2 3 4

C 0 1

D 1 2

💡 Hint

Remember that break exits the loop immediately.

The loop prints i values 0 and 1. When i == 2, it breaks before printing. So output is 0 1 .

🧠 Conceptual

expert

Number of iterations in nested loops with variable increments

Consider this C code snippet:

int count = 0;
for (int i = 1; i <= 4; i += 2) {
    for (int j = 0; j < i; j++) {
        count++;
    }
}

What is the final value of count after the loops finish?

A 4

B 10

C 8

D 12

💡 Hint

Calculate how many times the inner loop runs for each i value.

The outer loop runs for i = 1 (inner loop: 1 iteration) and i = 3 (inner loop: 3 iterations). Total: 1 + 3 = 4. Final value of count is 4.