Objective
The purpose of this lab is to illustrate the use of the if statement to make decisions in code. An if statement will execute a block of code if some specified condition is met. The goal of this lab is for you to become comfortable with the if statement syntax and how you create the condition expressions.
Software Tools
Tool | About | Installers |
Installation
Instructions |
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MPLAB® X
Integrated Development Environment |
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MPLAB® XC16
C Compiler |
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Exercise Files
File | Download |
Installation
Instructions |
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Windows | Linux | Mac OSX | ||
Project and Source Files
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Procedure
1
Open the Project
Start MPLAB® X IDE, then click on the Open Project icon on the main toolbarNavigate to the folder where you saved the exercise files for this class.
Click on the Lab05.X folder.
Select Open Project .3
Edit Source File
Search the code for lines with the comment “//### Your Code Here ###”. There will be additional comments above these lines with complete instructions, and in some cases, there will be comments to the right with specific details regarding a particular line of code.
Note that comments with instructions for your tasks are surrounded by ‘#’ to make them easy to spot.
STEP 1:
Increment intVariable1 if BOTH the following conditions are true:
floatVariable2 is greater than or equal to floatVariable1
charVariable2 is greater than or equal to charVariable1
Remember to use parentheses to group operations. This step will require you to use logical operators such as ‘&’ and relational operators such as ‘>=‘.
STEP 2:
If the above is not true and floatVariable1 is greater than 50 then decrement intVariable1 (Hint: else if).
STEP 3:
If neither of the above is true, set charVariable2 equal to 1. (Hint: else)
This code you are writing implements the flowchart below:
4
Debug Project
Once you finish writing the code:
Click on the Debug Project button. This will build and send the program to the simulator.Click on the Continue button. This begins the simulation.
Click on the Halt button. This will stop execution so that we may examine the variables and their values.
Open the Variables Window with either Window -> Debugging -> Variables or ( Alt + Shift + 1)
Results
5
End Debug Session
End the Simulation Session by clicking the Finish Debugger Session button.Close the Project.
Conclusions
The if statement makes it possible to execute blocks of code only when some specified set of conditions are met. When used in conjunction with the else if and else statements (which can only be used following an if statement), it is possible to drill down through several levels of conditions and execute a different block of code for each level.