1.2 Variables and Arithmetic Expressions

• All variables must be declared before they are used
• A declaration announces the properties of variables

1.1 Hello World

• C program consist of functions & variables
• Functions contain statements that specify the computing operations
• Variables stores value used during the computation
• Program begins executing at the beginning of "main" function 
• Arguments are data values of functions (surrounded by parentheses)
• On method of communicating data between functions is for the calling function to provide a list of values, called arguments, to the function it calls

Introduction

• C is a general-purpose computer programming language for use with the Unix operating system
• B is "typeless" language; C provides a variety of data types
• Fundamental data types are integer, character & floating point
• Hierarchy of derived data types created with pointers, arrays, structures and unions
• C provides the fundamental control-flow constructions required for well-structured programs: 
• statement grouping
• decision making (if-else)
• selecting one of a set of possible cases (switch)
• looping with termination test at the top (while, for)
• looping with termination test at the bottom (do)
• early loop exit (break)
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