Find Minimum Value of an Array in C

What You’ll Learn

Finding the minimum in an unsorted array is the twin of the max scan: keep a running winner and update it whenever you see a smaller value. This tutorial covers find_min, sizeof for length, a live preview, worked C examples (mixed positives and all negatives), edge cases, and O(n) complexity.

📝 Problem & Approach

Given a non-empty array of integers, return the smallest value with a single left-to-right scan.

/* Array: 12, 5, 7, 3, 2, 8, 10
 * Start min = 12
 * 5 < 12 → min = 5
 * 3 < 5  → min = 3
 * 2 < 3  → min = 2
 */

Inputs & Outputs

Minimal workflow

function find_min(arr, size):   // assume size >= 1
    min ← arr[0]
    for i from 1 to size - 1:
        if arr[i] < min:
            min ← arr[i]
    return min

Method comparison

🔮 Live Preview

Uses the same seven integers as Example 1: 12, 5, 7, 3, 2, 8, 10.

Press “Find minimum”.

Examples Gallery

Two complete C programs — a mixed sample (min 2) and an all-negative demo (min -9). Click View Output to reveal sample console results.

#include <stdio.h>

int find_min(const int arr[], int size) {
    int min_val = arr[0];

    for (int i = 1; i < size; ++i) {
        if (arr[i] < min_val) {
            min_val = arr[i];
        }
    }

    return min_val;
}

int main(void) {
    int array[] = {12, 5, 7, 3, 2, 8, 10};
    int size = (int)(sizeof(array) / sizeof(array[0]));
    int min_value = find_min(array, size);

    printf("Minimum value in the array: %d\n", min_value);

    return 0;
}

Minimum value in the array: 2

#include <stdio.h>

int find_min(const int arr[], int size) {
    int min_val = arr[0];
    for (int i = 1; i < size; ++i) {
        if (arr[i] < min_val) {
            min_val = arr[i];
        }
    }
    return min_val;
}

int main(void) {
    int negatives[] = {-9, -3, -1, -7};
    int n = (int)(sizeof(negatives) / sizeof(negatives[0]));

    printf("Minimum (most negative): %d\n", find_min(negatives, n));

    return 0;
}

Minimum (most negative): -9

🔎 Worked Walkthrough — Reference Array

Trace the running minimum for {12, 5, 7, 3, 2, 8, 10}.

Final answer: 2.

🔄 Input / Output

These programs use fixed numbers inside the code. To read values from the keyboard, use scanf in a loop, fill an array, then call find_min with the count you read.

🎯 Practice Problems

Try these variations to lock in the pattern.

Notes

⏱️ Time and Space Complexity

💡 Best Practices