Page Comparison

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C++	Blocks
Code Block language cpp /* multi-line comment */ Code Block language cpp // single line comment	Image RemovedImage Added Image Removed Image Added

Statements

• Statements are compiled into an ‘executable’ of 1s and 0s, which are run on the Arduino.

• Statements end with a ;

C++	Blocks
Code Block language cpp c = a+b; // c is assigned the sum of a, b	Image Removed Image Added

Variables

• Variables are containers to store intermediate data

• In C language, a variable needs to have a type, which specifies the nature and the size of data it holds

• Some of the standard data types are

• int : 16-bit integers in the range -32,768 to 32,767

• unsigned int : 16-bit positive integers (incl 0), 0 to 65535

• char : 8-bit integers from -128 to 127. Characters such as ‘0’, ‘A’, ‘a’, etc. are represented using ASCII (48, 65, 97 respectively - read up more!). BYTE is the same as unsigned char

• float : for floating point numbers such as 2.25, -5.875 (32-bits)

• Types can also be user-defined (through classes)

• Variables can be declared with or without initialization

C++	Blocks
Code Block language cpp int a; // declaration int a = 0; // declaration and initialization	Image RemovedImage Added Note: Creating a variable in Blocks declares it and initializes it to 0

A variable appearing on the left-hand side of an assignment statement assigns a value to it.

C++	Blocks
Code Block language cpp a = 10; // assigning 10 to a	Image RemovedImage Added

A variable value is used when it appears in a comparison or on the right-hand side of an expression/assignment.

C++	Blocks
Code Block language cpp (a == 1) // checking if a is equal to 1	Image RemovedImage Added
The comparison above returns a 'true' or 'false', which is usually used for selection or iteration. Read up more about comparison operators! Important : In C++, '==' is a comparison operator, '=' is the assignment operator. Using one instead of the other will not cause a syntax error, but will cause incorrect program functionality.

C++	Blocks
Code Block language cpp b = a + 10; // variable b is assigned the value of variable a plus 10.	Image RemovedImage Added

Selection

• A program that executes all the statements in a sequence is probably not very interesting.

• Sometimes, a part of a program must be executed based on a certain condition (selection).

• Given below is an example of an if-else statement. The {} is optional if there is only one line being executed conditionally for if or else.

C++	Blocks
Code Block language cpp if(a>0){ c = a+b; //executed when a>0 } else{ c = a-b; //executed when a<0 or a==0 }	Image RemovedImage Added

To Do : Read up about switch-case

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• Sometimes, a part of a program must be executed repeatedly until a certain condition is satisfied (iteration / loop)

• Given below is an example for an while loop.

C++	Blocks
Code Block language cpp while(a>0){ a = a-b; /* executed over and over until a<0 or a==0 */ }	Image RemovedImage Added

To Do : Read up about for loop, do-while loop

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C++	Blocks
Code Block language cpp {   digitalWrite(11, HIGH); }	Image RemovedImage Added

Setup() and loop() functions

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