C PROGRAMMING PROGRAM • ARRAYS, SEARCHING & SORTING

Sort an Array Using Insertion Sort

Learn how to sort an array using insertion sort using a clear C program.

IntermediateInsertion sortSorted prefixShift

PROBLEM UNDERSTANDING

Input and expected output

Sample input

6
12 11 13 5 6 7

Sample output

5 6 7 11 12 13

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int size, values[100];

    scanf("%d", &size);
    if (size < 1 || size > 100) return 1;
    for (int index = 0; index < size; index++) scanf("%d", &values[index]);
    for (int index = 1; index < size; index++) {
        int key = values[index], position = index - 1;
        while (position >= 0 && values[position] > key) {
            values[position + 1] = values[position];
            position--;
        }
        values[position + 1] = key;
    }
    for (int index = 0; index < size; index++) printf("%d%c", values[index], index == size - 1 ? '\n' : ' ');
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

5 6 7 11 12 13

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Remove each key from the unsorted part and insert it into its position in the sorted prefix.
Display the computed result.

Remove each key from the unsorted part and insert it into its position in the sorted prefix.

EFFICIENCY

Time and space complexity

Time complexity

O(n²)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.