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Insight Through Computing a
b
c
d
r1
r2 =
=
=
=
=
= x^2 + 5x + 6 = 0 1;
5;
6;
sqrt(b^2  4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) Insight Through Computing Assignment Statements Variable
Name
where to
put the value = Script Execution a Arithmetic
Expression a
b
c
d
r1
r2 a recipe for
computing a
numerical
value =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) b
c
d
r1
r2 Insight Through Computing Insight Through Computing Script Execution Script Execution 1 a
b
c
d
r1
r2 =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) 1 a
b
c
d a
b
c
d
r1
r2 =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) r1 5 b
c
d
r1 r2
Insight Through Computing a r2
Insight Through Computing 6 1/28/14 Script Execution Script Execution 1 a
b
c
d
r1
r2 =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) a 5 b 6 c
d 1
a
b
c
d
r1
r2 =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) a 5 b 6 c 1 d r1 r1 r2
Insight Through Computing r2
Insight Through Computing Script Execution Script Execution 1 a
b
c
d
r1
r2 =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) 1 5 b 6 c 1 d 3 a
b
c
d
r1
r2 =
=
=
=
=
= 1;
5;
6;
sqrt(b^2 4*a*c);
(b  d)/(2*a)
(b + d)/(2*a) r1
r2 Insight Through Computing Insight Through Computing Remember… Instructions are executed in order. In assignment statements, the right hand side is evaluated ﬁrst and then the value is assigned to the variable named on the left hand side. The variables on the right hand side must have values before they can be used in an expression. Insight Through Computing a 5 b 6 c 1 d 3 r1 2 a r2 Question Time What is the value of X and Y after the
following script is executed:
X
Y
X
X =
=
=
= 2;
7*X;
Y;
X + 1; A: X is 5 and Y is 14 C: X is 5 and Y is 21 B: X is 15 and Y is 14 D: X is 15 and Y is 2 Insight Through Computing 7 1/28/14 Question Time Input & Output • What about input and output? What is the final value of X and Y ?
>
>
>
>
> X
Y
X
X
Y A: =
=
=
=
= 8;
X;
Y;
2*X;
Y/2;
C: B: X is 8 and Y is 8 X is 16 and Y is 4 D: X is 16 and Y is 16 X is 8 and Y is 4 Insight Through Computing Insight Through Computing % Example 1_1: Surface area of a sphere
% A: surface area of the sphere
% r: radius of the sphere r= input('Enter the radius: ');
A= 4*3.14159*r*r;
fprintf('Surface area is %f!\n', A) n༆ variable = input(‘prompt ’) n༆ Lecture 2 Inpu...
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This document was uploaded on 03/11/2014 for the course CSCI 004 at Brown.
 Spring '14
 Potter
 Algorithms

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