REVIEW OF C-LANGUAGE BASICSTYPES1 byteSigned charactersigned char2 bytesUnsigned integerunsigned int4 bytesLong integerlongint8 bytesDouble precision F.Pt.No.double4 bytesFloating point no.float1 byteSingle characterchar2 bytesintegerintMemory requirementDef.Data type

Constants An immediate absolute value4 main types

A,b,HelloString constantsA,bCharacter constants0.12, 12.3, 6.6e6, 6.7E5, 5.5e-7Floating point constants6, 7Integer constantsexampleType

Character escapesFound within character and string constantsThese are characters not represented on keyboardBegin with backslash \

A single slash\\Single quote\Double quote\Carriage return\rbackspace\bNew line\ndefinitionCharacter escape

Declarations- tells the compiler the name and type of variable to be usedSimplest Form consists of

typeVariable name;char c;int I;float f; For several variablestypeVariable name,Variable name;char c1, c2, c3;

Declarations continuedWe can initialise our variables when they are declared; this consists of

typeVariable name=constant;e.g float n1 = 0.78e-3; For multiple variables we havetype,;e.g. char c1 = A, c2 =b;

Declarations ContinuedReasons why we declare variables before useThe compiler knows what kind/size of storage to allocateIt forces the programmer to pick the appropriate variables

Variable namesVariable names/identifiers need to reflect what they representC is case sensitive so approx and Approx will be treated as separate variablesThe identifiers can consist of numbers, letters and the underscore, but must always begin with a letter

Arithmetic Operators5 main operators :-modulus%division/multiplication*subtraction-addition+definitionoperator

Operators ContinuedC follows the standard operator hierarchy which can be controlled by parenthesis e.gY = (a + b) * (c d)(a + b) and (c d) will be executed 1stThe results of which will be multiplied and stored in the variable y

Assignment OperatorsThe assignment operator = assigns a value to a variable e.g.x = 1; a = b = c; a = b; i = i + 2; this sets x to 1 this copies the value of b into a this increments the current value of i by 2the value of c is copied into a and b

Type CastingThe value of an expression can be converted into a different data typeSyntax :- ((data type) expression)

b = 3;a = 6.542;y = ((int) a + b) % 4The result of y would be 1 9.5429Remainder of 9 divided by 4

Unary OperatorThese operators act on a single operand to generate a new valueUnary Minus --(x + y)Sum x and yReverse the sign

Increment operatorThe increment operator causes its operand to increment by 1

Post incrementVariable ++This increments the variable by 1 after the statement is executedPre increment++Variable This increments the variable by 1 before the statement is executed

Increment operator continuedi = 1;printf(i = %d \n, i);i = 1OUTPUTprintf(i = %d \n, ++i);i = 2printf(i = %d \n, i);i = 2THIS IS AN EXAMPLE OF THE PRE-INCREMENT UNARY OPERATOR

Increment operator continuedi = 1;printf(i = %d \n, i);i = 1OUTPUTprintf(i = %d \n, i++);i = 1printf(i = %d \n, i);i = 2THIS IS AN EXAMPLE OF THE POST-INCREMENT UNARY OPERATOR

The decrement operator --The increment operator causes its operand to decrease by 1

Post decrementVariable This decreases the variable by 1 after the statement is executedPre decrementVariable This decreases the variable by 1 before the statement is executed----

Decrement operator continuedi = 5;printf(i = %d \n, i);i = 5OUTPUTprintf(i = %d \n, --i);i = 4printf(i = %d \n, i);i = 4THIS IS AN EXAMPLE OF THE PRE-DECREMENT UNARY OPERATOR

Decrement operator continuedi = 5;printf(i = %d \n, i);i = 5OUTPUTprintf(i = %d \n, i--);i = 5printf(i = %d \n, i);i = 4THIS IS AN EXAMPLE OF THE POST-DECREMENT UNARY OPERATOR

Relational and Logical OperatorsThere are 4 relational operators in c

OperatorDefinitionGreater than=Greater than or equal to

Relational and Logical OperatorsThere are two equality operators in c

OperatorDefinition= =Equal to!=Not equal to

Relational and Logical OperatorsThere are two logical operators in c

The Relational and Logical Operators are found in conditional statements

OperatorDefinition&&AND||OR

Other Assignment Operatorsj = j % cj %= c%=b = b/3b /= 3/=a = a * (i 3)a *= (i 3)*=j = j b j -= b-=j = j + 7j += 7 +=Definition ExampleOperator

The Conditional OperatorThe ? Operator requires 3 operands and takes the general form:Expression-1?Expression-2:Expression-3If Expression-1 is trueexecute

The Conditional OperatorThe ? Operator requires 3 operands and takes the general form:Expression-1?Expression-2:Expression-3If Expression-1 is Falseexecute

The Conditional Operator continuedFalseAs expression-1 is false y is assigned the value 200

Operator HierarchyHierarchyHighestLowest

Operator CategoryOperatorsAssociativityUnary- ++ -- ! R LArithmetic * / % L RArithmetic + - L RRelational< >= L REquality == != L RLogical And && L RLogical Or || L RConditional ?: R LAssignment= += -= *= /= %= R L