Can somebody explain to me this line of code from the give post "printf("extra characters: %s\n", line + len);"

Question

Please see the post

Given the below data in the file:

Jim: 100.00 Amed

John: 200.00

if (line[len] != '\0') {                    
    printf("extra characters: %s\n", line + len);
}

the first invalid line will be:

Jim: 100.00 Amed

and the len 12 and the output will be:

extra characters: Amed

How does line + len give:

Amed

Answer 1

line + len will increment line's value (a memory address) by the size of its underlying data type.

So if line originally was:

Jim: 100.00 Amed

line + 12 would evaluate to:

Amed

See also: Pointer Arithmetic and c-faq.com section 4