ES101 - Lesson 2 : printf - Revision history

Preet: /* printf */

2013-09-05T17:18:43Z

‎printf

Preet: /* Operators */

2013-09-04T23:04:38Z

‎Operators

Preet: /* Assignment */

2013-06-10T21:31:55Z

‎Assignment

Preet at 00:40, 27 February 2013

2013-02-27T00:40:29Z

Preet at 00:35, 27 February 2013

2013-02-27T00:35:48Z

Preet: /* Assignment */

2013-02-21T19:04:42Z

‎Assignment

Preet: /* Variable Declaration */

2013-02-15T22:56:38Z

‎Variable Declaration

Preet: /* Assignment */

2013-02-13T00:53:56Z

‎Assignment

Preet: /* printf */

2013-02-13T00:50:26Z

‎printf

Preet: /* Variable Assignment */

2013-02-13T00:48:51Z

‎Variable Assignment

@@ Line 148: / Line 148: @@
 printf("Value of my_int = %i and value of my_float = %f\n", my_int, my_float);
 // The order of % should match order of variables on the right hand side after the comma
 </syntaxhighlight>
@@ Line 205: / Line 210: @@
 <BR/>
 == Assignment ==
 To provide output from the Board to your computer's PC, you need to open Hercules Program at 38400bps by going to the Serial Tab. Also note that after you open the COM Port in Hercules, the reset button should be pressed on the Board.

@@ Line 64: / Line 64: @@
 </syntaxhighlight>
 == Operators ==
 C/C++ has many "operators", but here are the basic assignment operators and examples:

@@ Line 206: / Line 206: @@
 == Assignment ==
 To provide output from the Board to your computer's PC, you need to open Hercules Program at 38400bps by going to the Serial Tab. Also note that after you open the COM Port in Hercules, the reset button should be pressed on the Board.
-# Declare a char variable and set it to the value of 75.
+# Declare and print a few char variables :
-#* Print this variable using printf using %c
+#* Declare a char variable and set it to the value of 75.
-# Declare another char variable and set it to the value of 'K'.
+#* Declare another char variable and set it to the value of 'K'.
-#* Print this variable using printf using %c
+#* Print these variable using printf using %c and %i using a single '''printf''' statement.
-# Note down the printed text for 1a and 2a (discuss during demo)
+#*: Example print-out: "The variables are K and K with integer value of 75 and 75"
-# Inches to centimeter converter :
+# Design a midterm percentage calculator :
-#* Declare a variable called "inches" and set it to an inch value, such as "24"
+#* Declare "float" variables to hold the following information:
-#* Declare another variable called "cm" and set it to "inches * 2.54"
+#*: Maximum score, user's score, and percentage
-#* Print both of these variables out.
+#* Set the maximum score variable to 50
-#* What variable types did you pick and why?  Be sure to pick something that hold fractional numbers.
+#* Set the user's score variable to 45
-# Note and discuss the results of the output of the next sub-bullets.
+#* Calculate the percentage, store it to the percentage variable and print it out.
-#* Print the centimeters' variable using printf using %f
+#*: Note that you should only print 2 decimal digits of the percentage and also print the percent symbol :
-#* Print this variable using %0.3f
+#*: Example: "Based on 45/50, your percentage is: 90.00%"
-#* Print this variable using %i
 === Sample Code ===

@@ Line 54: / Line 54: @@
 | Fractional numbers
 |}
 === Variable Declaration ===
@@ Line 64: / Line 63: @@
 int myInt = 3;     // Declare signed int and set to to 3
 </syntaxhighlight>
 === Variable Assignment ===
@@ Line 90: / Line 129: @@
 <br/>
-=== printf ===
+== printf ==
 The printf function can be used to output information from a program. In this class, the processor outputs the printf data to the USB Port, and you will open the USB Port in Hercules to view the data. But if you were writing your code on Windows PC, a DOS-based window would output the data.
@@ Line 164: / Line 203: @@
 |}
-<br/>
+<BR/>
 == Assignment ==
 To provide output from the Board to your computer's PC, you need to open Hercules Program at 38400bps by going to the Serial Tab. Also note that after you open the COM Port in Hercules, the reset button should be pressed on the Board.

@@ Line 164: / Line 164: @@
 |}
 == Assignment ==
 To provide output from the Board to your computer's PC, you need to open Hercules Program at 38400bps by going to the Serial Tab. Also note that after you open the COM Port in Hercules, the reset button should be pressed on the Board.

@@ Line 57: / Line 57: @@
 === Variable Declaration ===
-A variable must be declared before it can be used. To declare a variable, you simply specify the type, and the variable name. A meaningful name should be given to your variables. A variable name cannot contain spaces, and must start with a letter or underscore. Using a floating-point numbers is discouraged unless absolutely necessary because it is typically very slow to process floating-point numbers (such as add or divide) when compared to integers. Below are some examples of variable declarations.
+A variable must be declared before it can be used. To declare a variable, you simply specify the type, and the variable name. A meaningful name should be given to your variables. A variable name cannot contain spaces, and must start with a letter or underscore. Using a floating-point numbers is discouraged unless necessary because it is typically very slow to process floating-point numbers (such as add or divide) when compared to integers. Below are some examples of variable declarations.
 <syntaxhighlight lang="c">
-int i;         // Declare variable i
+/* ALWAYS set variables to 0 when declaring them */
-float myFloat; // Declare fractional number
+int i;             // Declare UNINITIALIZED variable i (not recommended)
-int myInt = 3; // Declare signed int and set to to 3
+float myFloat = 0; // Declare fractional number and set to 0
 </syntaxhighlight>
 === Variable Assignment ===

@@ Line 167: / Line 167: @@
 == Assignment ==
 To provide output from the Board to your computer's PC, you need to open Hercules Program at 38400bps by going to the Serial Tab. Also note that after you open the COM Port in Hercules, the reset button should be pressed on the Board.
-# Declare a char variable and set it to the value of 75. a.
+# Declare a char variable and set it to the value of 75.
 #* Print this variable using printf using %c
 # Declare another char variable and set it to the value of 'K'.
 #* Print this variable using printf using %c
-# What printed on the screen for 1a and 2a?
+# Note down the printed text for 1a and 2a (discuss during demo)
 # Declare an integer and set it to 10.
 #* Print this variable using printf using %i
 # Declare a floating point variable and set it to 10.00123.
-#: Log and discuss the results of the output of the next sub-bullets.
+#: Note and discuss the results of the output of the next sub-bullets.
 #:* Print this variable using printf using %f
 #:* Print this variable using %0.3f
 #:* Print this variable using %i
-# Repeat the previous question (a, b, and c), but use only 1 printf statement.
+# printf ALL of the variables you used, but use only ONE printf statement.
 === Sample Code ===
@@ Line 197: / Line 197: @@
 </syntaxhighlight>
-=== Questions ===
+=== Questions you need to answer during the demo ===
 *  What is the output if you try to print an integer, but use %f instead of %i ?
 *  What happens if you try to printf a variable that hasn't been declared?

@@ Line 111: / Line 111: @@
 </syntaxhighlight>
-Normally, printf will output anything inside double quotes, except when it encounters the % symbol. When the % symbol is encountered, print doesn‟t print %i, but instead, looks on its right hand side to convert a number to its ASCII representation and prints out the number. The sequence of %i correspond to the sequence of arguments given after the end of the double quotes. %i is to print an integer, however, if you wish to print other types of numbers, the %i needs to be changed. See the table below to find out the various different variables you can print. There are more specifiers, and you can reference your textbook for details.
+Normally, printf will output anything inside double quotes, except when it encounters the % symbol. When the % symbol is encountered, print doesn't print %i, but instead, looks on its right hand side to convert a number to its ASCII representation and prints out the number. The sequence of %i corresponds to the sequence of arguments given after the end of the double quotes. %i is to print an integer, however, if you wish to print other types of numbers, the %i needs to be changed. See the table below to find out the various different variables you can print. There are more specifiers, and you can reference your textbook for details.
 {| class="wikitable"