Every program uses data, either explicitly or implicitly, to arrive at a result. All programs specify a set of operations that are to be applied to certain data in a certain sequence. Data in its most primitive forms inside a computer is just a collection of bits.

Data Types Designing a computer language requires choosing which data types to build in, and which ones must be defined by users The tradeoff is one of expressiveness vs. efficiency Expressiveness refers to the ability to clearly express solutions to …

In programming language, input and data are stored in variables. There are several types of variables. One needs to declare a variable to tell the compiler about the data type and the name of the variable. Several basic types like int, float, char are present in C language.

Data types •A data type specifies: –The set of values that data of that type can have (e.g. integer, real, character, Boolean, colour, Greek letter, city, etc.) –The type of operations that can be performed with the data. For example, two integer numbers can be added, the population of a city can be calculated, etc.

data type is a set of values (the data) and a set of operations defined on the data. An implemen-tation of a data type is an expression of the data and operations in terms of a specific programming language such as Java or C++.

Some of the basic data types can be augmented by using certain data type qualifiers: •short •long •signed •unsigned Typical examples: •short int •long int •unsigned int •unsigned char

Data types In many programming languages, variables have types: e.g., int32, char *, or dict. The type of a variable tells us what kind of values we can assign to it: e.g, a variable of type int32 can hold a signed integer that fits in 32 bits, using two's complement representation to …

What has a type? What are types good for? What do we mean by type? record, tuple, map. type equivalence: when are the types of two values the same? type compatibility: when can a value of type A be used in a context that expects type B? type inference: what is the type of an expression, given the types of the operands?

Variable: an item of data named by an identifier Operators: - Arithmetic - Relational and Conditional - Assignment Expression: “a series of variables, operators and method calls that evaluates to a single value”

Value (data) types in python: Integers (type int): 0, 1, -3, … Floating-point numbers (type float): 1.0, 0.2, … Text (a.k.a. “string”, type str): “cool”, ’zero’, “1.03”, … “Boolean” truth values (type bool): False and True. ...and many more we’ll see later. Types determine what we can do with values (and sometimes what