TI-Basic 89 Programming/Conditional Functions

If If, Control(F2):1 is a command which will determine whether or not the next line of code is executed. Syntax: If If condition Where condition is an expression that resolves to be either true or false If condition is true, then the code in the next line is executed. Otherwise that code is skipped. Ex: If 5→x If x=5 Disp "True" True If...Then blocks If...Then...EndIf If...Then...EndIf, Control(F2):2:1 is a group of commands which will determine whether or not a block of code is executed. Syntax: If...Then...EndIf If condition Then code-block EndIf Where condition is an expression that resolves to be either true or false If condition is true, then the code in code-block is executed. Otherwise that code is skipped Where code-block has one or more lines of code Ex: If...Then...EndIf 5→x If x=5 Then 7→y Disp "Y is",y EndIf Y is 7 If...Then...Else...EndIf If...Then...Else...EndIf, Control(F2):2:2 is a group of commands which will determine which of two blocks of code is executed. Syntax: If...Then...Else...EndIf If condition Then code-block 1 Else code-block 2 EndIf Where condition is an expression that resolves to be either true or false If condition is true, then the code in code-block 1 is executed. Otherwise it skips to code-block 2 Where code-block 1 and code-block 2 each have one or more lines of code Ex: If...Then...Else...EndIf 8→x If x=5 Then Disp "X is five" Else Disp "X is not five" EndIf X is not five ElseIf...Then ElseIf...Then, Control(F2):2:3 is a command in which could be used to add more than two code blocks in If...Then...EndIf code. Syntax: ElseIf...Then If condition 1 Then code-block 1 ElseIf condition 2 Then code-block 2 EndIf Where condition 1 and condition 2 are expressions that resolves to be either true or false If condition n is true, then the code in the respective code-block n is executed. Otherwise it skips to the next ElseIf...Then statement, to a code-block between Else and EndIf, or straight to EndIf depending on how everything is setup. Where code-block 1 and code-block 2 each have one or more lines of code Ex: ElseIf...Then 8→x If x=5 Then Disp "X is five" ElseIf x=8 Then Disp "X is eight" EndIf X is eight Ex: ElseIf...Then with Else 8→x If x=5 Then Disp "X is five" ElseIf x=8 Then Disp "X is eight" Else Disp "X is neither 5 nor 8" EndIf X is eight