Programming in C (3rd Edition)

To make it short:

1. new allocates memory (e.g. for the sum) (see details)
2. strtoul converts a string to a long (see details)
3. I think you should start with a good C++ book (e.g. C++ Primer) and learn some C later (e.g. from this book). After that I would start with CUDA.

Keep your chin up.

Reference Style - All Levels

• The C Programming Language (2nd Edition) - Brian W. Kernighan and Dennis M. Ritchie
• C: A Reference Manual (5th Edition) - Samuel P. Harbison and Guy R. Steele
• C Pocket Reference (O'Reilly) - Peter Prinz, Ulla Kirch-Prinz
• C - Traps and Pitfalls - Andrew R. Koenig (Bell Labs)
• The comp.lang.c FAQ - Steve Summit

Beginner

• Programming in C (3rd Edition) - Stephen Kochan
• C Primer Plus (5th Edition) - Stephen Prata
• C Programming: A Modern Approach (2nd Edition) - K. N. King
• A Book on C - Al Kelley/Ira Pohl
• The C Book (Free Online) - Mike Banahan, Declan Brady and Mark Doran
• Practical C Programming (3rd Edition) - Steve Oualline
• C: How to Program (6th Edition) - Paul Deitel & Harvey M. Deitel
• Head First C - David & Dawn Griffiths
• Beginning C (5th Edition) - Ivor Horton

Intermediate

• Object-oriented Programming with ANSI-C (Free PDF) - Axel-Tobias Schreiner
• C Interfaces and Implementations - David R. Hanson
• The C Puzzle Book - Alan R. Feuer
• The Standard C Library - P.J. Plauger
• 21st Century C - Ben Klemens
• Algorithms in C - Robert Sedgewick
• Pointers on C - Kenneth Reek
• Pointers in C - Naveen Toppo, Hrishikesh Dewan
• Understanding and Using C Pointers - Richard M Reese

Above Intermediate

• Expert C Programming: Deep C Secrets - Peter van der Linden
• Advanced C Programming by Example - John W. Perry
• Advanced Programming in the UNIX Environment - Richard W. Stevens

Uncategorized Additional C Programming Books

• Essential C (Free PDF) - Nick Parlante
• The new C standard - an annotated reference (Free PDF) - Derek M. Jones