Written: August 14, 2026
Sorting teaches comparison, swapping, and why off-by-one bugs love nested loops.
This walkthrough keeps the logic small and readable so you can type it, run it, and then change one input at a time to see what happens.
What you will build
You will fill a small integer array, then use a simple selection-style swap pass so each position keeps the next smallest value.
- Read n and the array elements
- For each index i, scan the rest of the array for a smaller value
- Swap when you find one
- Print the array after sorting
Working C example
#include <stdio.h>
int main(void) {
int n, i, j, temp;
int a[100];
printf("Enter count (1-100): ");
if (scanf("%d", &n) != 1 || n < 1 || n > 100) return 1;
for (i = 0; i < n; i++) {
if (scanf("%d", &a[i]) != 1) return 1;
}
for (i = 0; i < n - 1; i++) {
for (j = i + 1; j < n; j++) {
if (a[j] < a[i]) {
temp = a[i];
a[i] = a[j];
a[j] = temp;
}
}
}
printf("Ascending: ");
for (i = 0; i < n; i++) printf("%d ", a[i]);
printf("\n");
return 0;
}How the logic works
Read the program top to bottom: includes and main first, then the statements that change variables, then the print that proves the result.
If your output looks wrong, print the variables before and after the critical lines. That single habit catches most beginner bugs faster than rewriting the whole file.
Verify with duplicates and already-sorted input. If those pass, your comparisons are probably solid.
Common mistakes
Forgetting a semicolon, using the wrong format specifier in printf/scanf, and mixing up assignment (=) with comparison (==) are the usual culprits.
Compile with warnings enabled (`gcc -Wall`) so the compiler points at risky casts and unused variables before you chase them by hand.
Try this next
Change the sample inputs, add a second test case, and briefly note what stayed the same. Teaching yourself with tiny experiments sticks better than copying a longer program you never run.
When you can explain every line without looking, you are ready for the next exercise in the series.
