Digit Extractor - Problem

Given a 4-digit number, extract and print each digit separately on a new line.

For example, if the input is 1234, the output should be:

Each digit should be printed on its own line, starting from the leftmost (thousands place) to the rightmost (units place).

Input & Output

Example 1 — Basic 4-digit number

$ Input: number = 1234

› Output: 1 2 3 4

💡 Note: Extract each digit: thousands=1, hundreds=2, tens=3, units=4. Print each on a new line.

Example 2 — Number with zeros

$ Input: number = 5067

› Output: 5 0 6 7

💡 Note: Even with zero in hundreds place, each digit is extracted: 5, 0, 6, 7.

Example 3 — All same digits

$ Input: number = 7777

› Output: 7 7 7 7

💡 Note: When all digits are the same, each position still outputs the same digit.

Constraints

1000 ≤ number ≤ 9999
The input is guaranteed to be a 4-digit integer

Visualization

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Asked in

T TCS 15 I Infosys 12

The key insight is that each digit position in a number represents a power of 10. By dividing by the appropriate power of 10 and using modulo 10, we can extract individual digits mathematically. Best approach uses mathematical division without string conversion. Time: O(1), Space: O(1)

Common Approaches

✓ Mathematical Division Method

⏱️ Time: O(1) Space: O(1)

Extract digits using mathematical operations by dividing by powers of 10 (1000, 100, 10, 1) and using modulo 10 to get individual digits. This approach works directly with the number without string conversion.

String Conversion Method

⏱️ Time: O(1) Space: O(1)

Convert the 4-digit number to a string, then iterate through each character and print it. This approach treats the number as a sequence of characters rather than performing mathematical operations.

Mathematical Division Method — Algorithm Steps

Divide by 1000 to get thousands digit, use modulo 10
Divide by 100 to get hundreds digit, use modulo 10
Divide by 10 to get tens digit, use modulo 10
Use modulo 10 to get units digit

Visualization

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Step-by-Step Walkthrough

Thousands

1234 ÷ 1000 = 1 (remainder ignored)

Hundreds

1234 ÷ 100 = 12, then 12 % 10 = 2

Tens & Units

Similarly for tens (3) and units (4)

Code -

solution.c — C

#include <stdio.h>

void solution(int number) {
    // Extract thousands digit
    printf("%d\n", number / 1000 % 10);
    // Extract hundreds digit
    printf("%d\n", number / 100 % 10);
    // Extract tens digit
    printf("%d\n", number / 10 % 10);
    // Extract units digit
    printf("%d\n", number % 10);
}

int main() {
    int number;
    scanf("%d", &number);
    solution(number);
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(1)

Fixed 4 mathematical operations for a 4-digit number

✓ Linear Growth

Space Complexity

O(1)

Only uses a few integer variables

✓ Linear Space

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Digit Extractor - Problem

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Mathematical Division Method — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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