1. Completing the Basic (L06)
*Assignment Operations
* Formatting Numbers for Program Output
Completing the Basic Dr. Ming Zhang

2. Assignment Operations
* General Form of Assignment Statement
variable = operand;
* Constant Operand for Assignment
length = 25;
(is read, length is assigned the value 25)
* Overwritten with New Value
length = 6.28;
( The 25 that was in length is overwritten with new value of 6.28, because a variable can only store one value at a time)
Completing the Basic Dr. Ming Zhang

3. Expression as the Assignment Operand
An expression is any combination of constants and variables that can be evaluated to yield a result.
* Expression as the Operand of Assignment Statement
The expression in an assignment statement can be used to perform calculations using the arithmetic operators.
diff = ;
product = 5 * 6;
new_value=diff+product+20; /*new_value=60*/
Completing the Basic Dr. Ming Zhang

4. Exercise 1: the Value of a Circle Area (C++)
# Using C++, write a program to calculate
# the value of a circle area.
#include <iostream>
using std::cout;
int main( ) { … }
Output: The value of the circle area is
Completing the Basic Dr. Ming Zhang

5. Assignment Variations
The variable on the left of the equal sign can also be used the right of the equal sign in the assignment statement
sum = 20;
sum = sum +10; /* sum = 30 */
* Assignment expressions like sum = sum + 25, which use the same variable on both sides of the assignment operator, can be written using the following assignment operators:
+= -= *= %=
Completing the Basic Dr. Ming Zhang

6. Assignment Operators sum = 20 sum += 10; ( sum = sum + 10; sum = 30)
rate = 5;
sum *= rate; ( sum = sum*rate; sum = 10)
sum *= sum+2; (sum = sum*(sum+2); sum = 120)
sum *= rate+2; (sum = sum*(rate+2); sum = 840)
Completing the Basic Dr. Ming Zhang

7. Accumulating #include <iostream> int main(void) { int sum = 0;
cout <<“The value of sum is set to ”<<sum<<endl;
sum = sum +10;
cout << “sum is now ” << sum;
sum = sum +20;
return 0;}
Output:
The value of sum is set to 0
sum is now 10;
sum is now 30; /* sum is NOT 20*/
Completing the Basic Dr. Ming Zhang

8. Counting * Counting Statement Form variable = variable + fixed_number;
* Examples of Counting Statement
i = i + 1;
n = n + 1;
count = count + 1;
j = j +2;
m = m + 3
kk = kk + 4;
Completing the Basic Dr. Ming Zhang

9. Increment and Decrement Operators
* Increment Operators
i = i + 1; i;
n = n + 1; n;
count = count + 1; count;
* Decrement Operators
i = i - 1; i;
n = n - 1; n;
count = count - 1; count;
Completing the Basic Dr. Ming Zhang

10. Example of Increment Operators
#include <iostream>
int main(void)
{ int count = 0;
cout <<“The initial value of count is ” << count;
++count;
cout <<“count is now ” << count ;
++count; ++count;
cout <<“count is now ” << count;
return 0;}
Completing the Basic Dr. Ming Zhang

11. Exercise2 : Increment Operators (C++)
# Using increament operators and C++, write a
# program to print out on the screen:
# The initial value of count is 0.
# count is now 1.
# count is now 3.
#include <iostream>
using std::cout;
int main( ) { … }
Output:
Completing the Basic Dr. Ming Zhang

12. Data Type Conversion * Case Operator for Data Type Conversion
(data_type) (expression);
* Example
double a=2.3, b=5.0, product1;
int product2;
product1 = a * b; /* product1 =11.5 */
product2 = (int) (a*b); /* product2 = 11 */
product1 = (int) a * b; /*(int)a==2. product1 = 10.0*/
Completing the Basic Dr. Ming Zhang

13. Example of Data Type Conversion
#inlude <iostream>
using std::cout;
int main( )
{ double a=3.3, b=6.0, product1;
int product2;
product1 = a * b; /* product1 =19.8 */
product2 = (int) (a*b); /* product2 = 19 */
product1 = (int) a * b; /*(int)a==3. product1 = 18.0*/
cout << “product1=“ << product1 << endl;
cout << “product2=“ << product2 << endl;
return(0); }
Completing the Basic Dr. Ming Zhang

14. Exercise 3 : Data Type Conversion
# Read follwing program and find out the output
#inlude <iostream>
using std::cout;
int main( )
{ double a=5.3, b=4.0, product1;
int product2;
product1 = a * b;
product2 = (int) (a*b);
product1 = (int) a * b;
cout << “product1=“ << product1 << endl;
cout << “product2=“ << product2 << endl;
return(0); }
Completing the Basic Dr. Ming Zhang