Pointer arithmetic in C

Walking an array with pointers instead of indexes.

int sum_with_pointers(const int *items, int n) {
    const int *end = items + n;
    int total = 0;
    for (const int *p = items; p < end; p++)
        total += *p;
    return total;
}

How it works

1. items + n points just past the last element.
2. Incrementing p steps one element at a time.
3. *p reads the element under the pointer.

Keywords and builtins used here

• const
• for
• int
• return
• sum_with_pointers

The run, in numbers

Lines

7

Characters to type

161

Tokens

53

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 35 seconds.

Type this snippet

Step 3 of 5 in Pointers, step 3 of 25 in Pointers & memory.

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