The basics of the ZealC language. Requirements: Knowledge of basic integer mathematics and number sense. There are 4 main types of symbols. A symbol is just a fancy name for something with a name. We have: - Functions - Variables - Definitions - Classes //This is a variable I64 my_var; //This is another variable of a different type. U8 my_u8; Variables are declared as certaintypes. There are types for numbers. You just saw two of them above, I64 and U8. The compiler gives us 8 types for numbers. These types are differentsizesof numbers, and if they aresignedorunsigned. Abyteis 8 bits. The range of numbers you can store in a byte is 0 to 255. In a signed byte that range is from -128 to 127. * Unsigned types cannot be a negative value. * Only signed types can store negative numbers. Now you might be thinking, how does it know if a number is negative or not? After all, a number is just a series of bits! The way we store a signed number is we reserve a single bit in the number to tell us whether or not it is signed. If we have a number that is 8 bits wide, then we have to use a single bit as asign bit. The sign bit is always the highest bit available. In a signed byte, bits #0-6 will be used to store the actual value of the number. Bit #7 will be the sign bit. If the sign bit is 1, then it is a negative number. # 7 6 5 4 3 2 1 0 0b 0 0 0 0 0 0 1 1 => 3 | | | sign the number "3" in binary If it a number is signed that means that it cannot use all of its bits to represent a value. Therefore, the range of numbers it can represent is split between the negative side and the positive side of numbers. Unsigned byte range |----------------------------| Signed byte range |--------------------------| -255 -127 0 127 255 Now, you can imagine how this plays out with numbers that are bigger than 1 byte. For 2-byte numbers, the unsigned range becomes 0 to 65535, and the signed range becomes -32768 to 32767. The sign bit is bit #15. Unsigned number types: U8 -- 1 byte (8 bits) unsigned number I8 -- 1 byte (8 bits - 1 sign bit = 7 bits) signed number U16 -- 2 byte (16 bits) unsigned number I16 -- 2 byte (16 bits - 1 sign bit = 15 bits) signed number U32 -- 4 byte (32 bits) unsigned number I32 -- 4 byte (32 bits - 1 sign bit = 31 bits) signed number U64 -- 8 byte (64 bits) unsigned number I64 -- 8 byte (64 bits - 1 sign bit = 63 bits) signed number Try it out on the command line: Declare a I8 variable named 'x' and assign(=) it the value 3, and press ENTER. C:/Home>I8 x = 3; Now type Bts(&x, 7); and press ENTER. This will set bit #7 to 1. Bts is "Bit test and set". Don't forget the &. Now if you want to see the value of x, you can simply type x; and press ENTER. C:/Home>x; 0.000007s ans=0xFFFFFFFFFFFFFF83=-125 Ignore the extra F's for now. You are interested in this hexadecimal '83' value. So what happened? When you flipped the sign bit, the number 3 became -125. It started counting up from -128, instead of 0. You can type "%8tb\n", x; to print out the number in binary, if you wish. For most purposes in programming, an I64 number will work fine. You are currently reading this on a 64-bit operating system, running on a 64-bit computer. We hear about the greatness of 64-bit machines all the time, but what exactly does that mean? The CPU is designed to work with 64-bit numbers, natively.