Tutorial

Compiling the Program

C

gcc <input.c> -o output -Wall

C++

g++ <input.c> -o output -Wall

Note that attempting to compile a C++ file with gcc will fail with undefined reference to `__gxx_personality_v0'

-Wall turns on all compiler warnings, It is not necessary, but often useful to catch silly mistakes in the code.

Java

javac <input.java>

Data Representation

Numbers

Integers

Fixed Length

• char: 8 bits in C/C++, 16 bits in Java
• int: 32 bits
• long: 32 bits in C/C++, 64 bit in Java
• long long: 64 bits in C/C++, GCC only. (__int64 in Microsoft C++)

An n-bit signed integer can represent values int the range [-2^n-1, 2^n-1 - 1].
An unsigned integer can represent values in the range [0, 2ⁿ - 1] (Not available in Java)
Values are represented in 2's complement (mod 2ⁿ) during overflow.

Division rounds towards 0

• • (-5) / 3 = -1
  • 7 / 3 = 2
  • 1 / 2 = 0

Arbitrary Length

Java has BigInteger

• This is slow, but infinitely precise.

Floating Point

• Comparing Floating Point numbers