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14:440:127 Introduction to Computers for Engineers
Problems for students to attempt in Recitation 6 Solutions
1)
Write a
for loop
that calculates 20!
(20 factorial).
You may not use the factorial( )
function.
total=1;
for
x=1:20
% or 20:1:1
total=total*x;
end
disp(total)
2)
Write a
while loop
that continually asks the user to input a number. Each time he/she
enters a positive number, you should display that number to the screen.
Once the enter a
number that’s not positive, the loop should stop, and you should display “Loop Stopped”
to the screen.
x=input(
'Enter a number'
);
while
(x>0)
disp(x)
x=input(
'Enter a number'
);
end
disp(
'Loop stopped'
)
3)
Write a
for loop
that calculates the sum of the prime numbers from 1 to 1000.
total=0;
for
x=1:1000
if
(isprime(x))
total=total+x;
end
end
disp(total)
% without loops:
sum(primes(1000))
4)
Write a
while loop
that finds the smallest 8 digit prime number.
Then, instead write
that loop as a
for loop
(using the
break
command).
n=10000000;
% smallest 8 digit number
while
(~isprime(n))
% loop until you find a prime
n=n+1;
end
disp(n)
for
n=10000000:99999999
if
(isprime(n))
break
end
end
disp(n)
5)
Use the following command to create a 10x10 matrix:
C = round(500*rand(10));
Write a nested
for loop
that finds the maximum value in that matrix.
C = round(500*rand(10))
z=size(C);
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View Full Document maxval=inf;
for
r=1:z(1)
% z(1) is the number of rows in C
for
c=1:z(2)
if
(C(r,c)>maxval)
maxval=C(r,c);
% set maxval = to current number
end
end
end
disp(maxval)
% to write this without a nested loop
C = round(500*rand(10))
Cvector = C(:);
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This note was uploaded on 02/29/2012 for the course 440 127 taught by Professor Blase during the Fall '09 term at Rutgers.
 Fall '09
 blase

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