MATLAB Examples

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MATLAB Examples
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MATLAB Examples

• Find the number of positive numbers in a vector
• x input( 'Enter a vector ' )count 0for
  ii 1length(x), if ( x(ii) gt 0 ),
  count count 1 endendfprintf('Number of
  positive numbers is d\n', count)

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MATLAB Examples

• Find the index of the largest number in a vector
• x input( 'Enter a vector ' )max_value
  x(1)max_index 1for ii 2length(x), if
  ( x(ii) gt max_value ), max_value
  x(ii) max_index ii
  endendfprintf( 'Max value is d\n', max_value
  )fprintf( 'Its index is d\n', max_index )
• What if the max value occurs more than once?

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MATLAB Examples

• Print a triangle of stars in n rows
• n input( 'Enter the number of rows ' )for
  ii 1n, for jj 1ii, fprintf( ''
  ) end fprintf( '\n' )end

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MATLAB Examples

• Find the kth digit of a number (kth digit from
  the right)
• num input( 'Enter the number ' )k input(
  'Enter the digit from right you want '
  )num_orig numfor ii 1k-1, num fix(
  num / 10 )enddigit mod( num, 10
  )fprintf('Digit d of d is d\n', k, num_orig,
  digit)

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Example rock-paper-scissors game

• Generate computers choice
• aceil(rand(1)3)
• Get user input
• userinput(' enter 1 for rock \n enter 2 for
  paper \n enter 3 for scissors ')
• Display your choice
• if a1
• disp('I choose rock')
• elseif a2
• disp('I choose paper')
• else
• disp('I choose scissors')
• end
• Display user's choice
• if user1
• disp('You choose rock')
• elseif user2
• disp('You choose paper')
• else
• disp('You choose scissors')

• win0 2 1 1 0 2 2 1 0
• resultwin(user,a)
• Display result
• if result0
• disp('Settle for draw!')
• elseif result1
• disp('You win!')
• else
• disp('You are a loser!')
• end

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Example rock-paper-scissors game

• Display user's choice
• switch(user)
• case1
• disp('You choose rock')
• case2
• disp('You choose paper')
• otherwise
• disp('You choose scissors')
• end
• win0 2 1 1 0 2 2 1 0
• resultwin(user,a)
• Display result
• if result0
• disp('Settle for draw!')
• elseif result1
• disp('You win!')
• else
• disp('You are a loser!')

• Generate computers choice
• aceil(rand(1)3)
• Get user input
• userinput(' enter 1 for rock \n enter 2 for
  paper \n enter 3 for scissors ')
• Display your choice
• switch(a)
• case1
• disp('I choose rock')
• case2
• disp('I choose paper')
• case3
• disp('I choose scissors')
• end

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Example rock-paper-scissors game

• Display user's choice
• switch(user)
• case1
• disp('You choose rock')
• case2
• disp('You choose paper')
• otherwise
• disp('You choose scissors')
• end
• win0 2 1 1 0 2 2 1 0
• resultwin(user,a)
• Display result
• if result0
• disp('Settle for draw!')
• elseif result1
• disp('You win!')
• else
• disp('You are a loser!')
• end

• answer'y'
• while answer'y'
• Generate computers choice
• aceil(rand(1)3)
• Get user input
• userinput(' enter 1 for rock \n enter 2 for
  paper \n enter 3 for scissors ')
• Check for erroneous input
• while user1 user2 user3
• userinput(' enter 1 for rock \n enter 2 for
  paper \n enter 3 for scissors ')
• end
• Display your choice
• switch(a)
• case1
• disp('I choose rock')
• case2
• disp('I choose paper')
• case3
• disp('I choose scissors')
• end

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Example continue

• Get inputs from the user.
• arrayinput('Please enter the array to search
  ')
• ninput('Please enter the number to be searched
  ')
• Get size of the array.
• r csize(array)
• Search for n in the array.
• for ii1r
• fprintf('row d\n',ii)
• for jj1c
• fprintf(column d\n',jj)
• if(array(ii,jj)n)
• fprintf('d found at row d, column
  d\n',n,ii,jj)
• continue
• end
• end
• end
• fprintf(ii is d, jj is d\n', ii,jj)

• Output
• Please enter the array to search 2 4 5 6 13 2
  5 3 11
• Please enter the number to be searched 13
• row 1
• column 1
• column 2
• column 3
• row 2
• column 1
• column 2
• 13 found at row 2, column 2
• column 3
• row 3
• column 1
• column 2
• column 3
• ii is 3, jj is 3

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Example break
Output Please enter the array to search 2 4
5 6 13 2 5 3 11 Please enter the number to be
searched 13 row 1 column 1 column 2 column
3 row 2 column 1 column 2 13 found at row 2,
column 2 row 3 column 1 column 2 column 3 ii is
3, jj is 3

• Get inputs from the user.
• arrayinput('Please enter the array to search
  ')
• ninput('Please enter the number to be searched
  ')
• Get size of the array.
• r csize(array)
• Search for n in the array.
• for ii1r
• fprintf('row d\n',ii)
• for jj1c
• fprintf(column d\n',jj)
• if(array(ii,jj)n)
• fprintf('d found at row d, column
  d\n',n,ii,jj)
• break
• end
• end
• end
• fprintf(ii is d, jj is d\n', ii,jj)

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Example student grades

• Get inputs from user.
• gradesinput('Enter a grades matrix ')
• weightsinput('Enter a weights vector ')
• r csize(grades)
• multipzeros(r,c)
• overallzeros(r,1)
• pass0
• fail0
• max1
• Divide weights by 100 to obtain percent weights
• weightsweights/100
• weighttweights'
• calculate average by matrix multiplication
• overallgradesweightt
• print out overall grade
• for ii1r
• fprintf('Overall grade of student d
  .2f\n',ii,overall(ii))
• end

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Example student grades (contd.)

• Calculate pass/fail numbers
• if(overall(ii)gt65)
• passpass1
• else
• failfail1
• end
• Highest grade student
• if(overall(max)ltoverall(ii))
• maxii
• end
• end
• Print out number of passing / failing students
• fprintf('The number of passing students is
  d\n',pass)
• fprintf('The number of failing students is
  d\n',fail)
• Print out who got the highest overall grade.
• for ii1r