Rust common programming concepts

Covers Rust features similar to those of other programming languages.

• Constants
  • using the const keyword instead of the let keyword type of the value must be annotated
  • constants can be declared in any scope, including the global scope

Scalar Types

• integers
  • like unsigned u8 and signed i8
  • Signed and unsigned refer to whether it’s possible for the number to be negative
  • Signed numbers are stored using two’s complement representation
  • default integer type is i32, takes up 32 bits of space
    • this type is generally fastest, even on 64-bit systems
• floating-point
  • f32 f64
• numbers
  • the basic mathematical operations
    • addition
    • subtraction
    • multiplication
    • division
    • remainder
• booleans
• characters
  • char literals are specified with single quotes
  • char type is four bytes in size and represents a Unicode Scalar Value, which means it can represent a lot more than just ASCII

Compound Types

• Compound types can group multiple values into one type
• tuple
  • a general way of grouping together a number of values with a variety of types into one compound type
  • fixed length: once declared, they cannot grow or shrink in size
• array
  • Arrays in Rust are different from arrays in some other languages because arrays in Rust have a fixed length, like tuples

Functions

• We do declare their type after an arrow ->
• the body of the function is a lonely number with no semicolon, because it’s an expression whose value we want to return.

Control flow

• loop(err prone)
  • execute a block of code over and over again forever
• while(err prone)
  • evaluate a condition within a loop
  • cons
    • can cause the problems to panic if the index value or test condition are incorrect
    • slow due to the compiler adds runtime code to perform the conditional check of whether the indec is within the bounds of the array on every iteration through the loop
• for
  • .. is a range operator,which forms a Range object(or a derivative `RangeFrom`,`RangeFull` or `RangeTo`) those objects only contain indexes(the Idx type), so you can rest assured that `.len()` is only evaluated once.