CIS241

System-Level Programming and Utilities

C Arrays and Loops

Erik Fredericks, frederer@gvsu.edu
Fall 2025

Based on material provided by Erin Carrier, Austin Ferguson, and Katherine Bowers

C arrays

All elements in a C array have the same type

For now, we are talking about static arrays

• i.e., fixed size

Declaring:

• int arr[10];
• int arr[3] = {2, 4, 6};
• char arr[5];
• char arr[] = "hello world";

Array indexing

We still access elements like in every other language (zero-indexed)

• int arr[3] = {2, 4, 6};
• int x = arr[1];
• arr[2] = 0;

For loops

unsigned int i;
for (i = 0; i < 10; i++)
{
    ...
}

Newer versions of C allow you to create an iterative variable inside the loop line

While loops

while (condition)
{
    ...
}

int i = 10;
while (i >= 0)
{
    ...
    i--;
}

Do-while loops

do
{
  ...
} while (condition);

Same as while, but the block executes at least once!