Sheet 2

control structures

if condition

if (condition) statement

if (x == 100) cout

Relational and equality operators ( ==, !=, >, =, Greater than

< Less than

>= Greater than or equal to

Relational and equality operators ( ==, !=, >, =, 4) // evaluates to true. (3 != 2) // evaluates to true. (6 >= 6) // evaluates to true. (5 < 5) // evaluates to false.

Logical operators ( !, &&, || )

!(5 == 5) // evaluates to false !(6

Logical operators ( !, &&, || )

( (5 == 5) && (3 > 6) ) // evaluates to false ( (5 == 5) || (3 > 6) ) // evaluates to true

if condition

if (x == 100) { cout

if else

if (x == 100) cout

if else

if (x > 0) cout

Question 6 (Sheet 1)

Write a program that reads in the values for a, b, and c and find the roots of the polynomial:

2 + + = 0

Question 6 (Sheet 1)

Write a program that reads in the values for a, b, and c and find the roots of the polynomial:

2 + + = 0

2 4

2

Question 6 (Sheet 1)

a. The first coefficient is zero: Program terminates with an

error message.

b. Complex roots: Program prints solutions including the imaginary part.

c. One real solution: Program states that there is only one solution and prints it.

d. Two different real solutions: Program prints both normally.

Loops

Do I know the number of repetitions?

Yes (for loop) for (initialization; condition; increase) statement;

No (while and do-while) while (expression)

statement;

for loop

Question 1

Write a program that prints the square of all numbers from 1 to 20.

Question 2

Write a program that computes and displays the sum of odd integers in the range 0 to 100, inclusive.

Conditional operator ( ? )

X= (7==5) ? 4 : 3 // returns 3 X= (7==5+2) ? 4 : 3 // returns 4 X= 5>3 ? a : b //X=a

Question 4

Write a program to read a collection of exam scores ranging in values from 1 to 100. Your program should find and print the average score, the maximum and the minimum scores. the program will terminate if the value -99 is entered by the user.

Question 5

Write a program fragment that uses nested loops to produce the following output: 1 12 123 1234 12345 123456 1234567 12345678 123456789