06-C++ Expressions computer science

8/10/2019 06-C++ Expressions computer science

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C++ ExpressionsCMPT 111


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Demo! See demo1.cpp


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Exercise #1 Write a C++ program that will:

1. Ask the user to enter a temperature in Fahrenheit.

2. Read in that value.

3. Convert the value to Celsius

4. Print out a message telling the user what the convertedtemperature is.

)32(9

5 FC


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Demo: Functions See: http://www.cplusplus.com/reference

Example function prototypes:

double sin(double x);

double pow(double base, int exponent);

double pow(double base, double exponent);

int isdigit(int c);

int rand(void); OR int rand();

void srand(int seed);
http://www.cplusplus.com/referencehttp://www.cplusplus.com/reference


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Exercise #2 Using the cmath functions:

double cos(double x);

double sin(double x);

double tan(double x); double pow(double base, double exponent);

Write a C++ program that will input a floating point

value, x, and print out the values of:

tan(x)

sin(x)

cos(x)

sin2(x)+cos2(x)

(sin(x))cos(x)


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Relational Operators Relational operators:

, =, ==, !=

Careful not to confuse = with ==

= is assignment

== is a test for equality

Can compare any two things that are the same.

ex: two numbers (int vs. int, int vs. float, float vs. float)

ex: two characters

Compared lexicographically (using ASCII table)

ex: two strings

Compared lexicographically (using ASCII table)


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Boolean Operators Operate on boolean values.

Non-booleans are converted to boolean first, if possible.

numeric: 0 -> false; everything else -> true

Three operators: ! (not)

&& (and)

|| (or)


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Boolean NOT Unary operator

It is applied to a single boolean value

Changes true to false, and false to true.

As a set relation:

Everything not in the set

ex:

!true is false !false is true

!(x < 0) is the same as (x >= 0)

A!A


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Boolean NOT: Exercises

Given that:

x = 4

y = -3.1415926

What is the value of:

A) !(x > 0)

B) !(x < y)

C) !(x == y)

D) !(x < x)

E) !(y != x)


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Boolean AND Binary operator

Applied to a pair of boolean values (just like +)

Is true only if both values are true

As a set relation

Everything in both sets.

A B

A and B

A and B true false

true true false

false false false


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Boolean AND: Exercises

Given that:

x = 4

y = -3.1415926


A) (0 < x) && (x < 5)

B) (x < y) && (y < 0)

C) true && (x == 4)

D) (x != y) && ((x*y) < 0) && ((x-y) > 0)

E) !(x


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Boolean OR Binary operator

Applied to a pair of boolean values (just like +)

Is true when either value is true

As a set relation

Everything in either set.

A BA or BA or B true false

true true true

false true false


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Boolean OR: Exercises

Given that:

x = 4

y = -3.1415926


A) (0 < x) || (x < 5)

B) (x < y) || (y < 0)

C) true || (x == 4)

D) (x != y) && ((x*y) < 0) || ((x-y) > 0)

E) !(x


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Expressions In C++ Boolean Expressions are very similar to arithmetic

expressions

We can evaluate them and store their result

06-C++ Expressions computer science

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