Introduction to Programming
Dr. Yang, QingXiong(with slides borrowed from Dr. Yuen, Joe)
LT3: Conditional StatementsCS2311 Computer ProgrammingOutlines2if statementSimpleNested
Boolean logic
switch statement
Outcomes3Work out the boolean value of a logic expression
Express decision making logic in boolean logic
Using if / switch statement to express conditional instructions
Syntax Summary4Keywordsif, else, switch, case, default,Punctuators(){}:? :Operators==, !, !=, >, >=, 1&&bless than or equal to =Equality operatorsequal to==not equal to!=Logical operatorslogical not!logical and&&logical or||PS: Expressions with above operators have a true or false value.Precedence & associativity of popular operators11Operator precedence (high to low)Associativity*/%Left to right+-Left to right=Left to right==!=Left to right&&Left to right||Left to right?:Right to leftConditional statements12In decision making process, logical value can be used to determine the actions to take.
E.g. If it is raining, then bring an umbrellaIf AC1 canteen is too crowded, then go to AC2/AC3 for lunch
In programming, certain statements will only be executed when certain condition is fulfilled. We call them conditional statements.Conditional statement: if13One statement will be executed if the condition is trueSyntax:if (logical expression) statement;
Only one statement will be executedC++ example:
cin >>x;if (x=70 and mark
