Foreach loop over collections in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Foreach loop over collections

Start with collection

↓

Pick first item

↓

Execute loop body with item

↓

More items?

No→Exit loop

Yes↓

Pick next item

The foreach loop picks each item from a collection one by one and runs the loop body using that item until all items are processed.

Execution Sample

C Sharp (C#)

string[] fruits = {"apple", "banana", "cherry"};
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

This code prints each fruit name from the fruits array, one per line.

Execution Table

Iteration	Current item (fruit)	Action	Output
1	"apple"	Print fruit	apple
2	"banana"	Print fruit	banana
3	"cherry"	Print fruit	cherry
-	-	No more items, exit loop	-

💡 All items in the collection have been processed, so the loop ends.

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
fruit	null	"apple"	"banana"	"cherry"	null (loop ended)

Key Moments - 3 Insights

Why does the variable 'fruit' change each iteration?

Because foreach assigns the next item from the collection to 'fruit' each time, as shown in execution_table rows 1 to 3.

What happens when all items are done?

The loop stops automatically, as shown in the last row of execution_table where no more items remain.

Can we modify the collection inside the foreach loop?

No, modifying the collection during foreach can cause errors or unexpected behavior. The loop expects the collection to stay the same.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of 'fruit' during iteration 2?

A "cherry"

B "apple"

C "banana"

D null

💡 Hint

Check the 'Current item (fruit)' column at iteration 2 in the execution_table.

At which iteration does the foreach loop stop?

A After iteration 1

B After iteration 3

C After iteration 2

D It never stops

💡 Hint

Look at the exit_note and the last row in execution_table showing no more items.

If we add "date" to the fruits array, how many iterations will the loop have?

A 4

B 3

C 5

D Cannot tell

💡 Hint

The loop runs once per item in the collection, so adding one item increases iterations by one.

Concept Snapshot

foreach (type var in collection) {
  // use var inside loop
}

- Loops over each item in collection
- 'var' holds current item
- Stops after last item
- Collection should not change during loop

Full Transcript

The foreach loop in C# goes through each item in a collection one by one. It assigns the current item to a variable and runs the loop body using that item. When all items are done, the loop stops automatically. You cannot change the collection while looping. This example prints each fruit name from an array. The variable 'fruit' changes each iteration to the next fruit. The loop ends after the last fruit is printed.