# Tag Archives: loops

# Array Fun 1 [Java]

Array Fun 1

Create a Class called ArrayFun that has the following methods Write the body for the methods described below.

**public int[] swapFirstLast(int[] nums)**

Description:This method returns a new version of the array with the first and last elements of`nums`

swapped.

Method Call |
return value/output |

swapFirstLast( {3, 2 ,5 } ) | {5,2,3} |

swapFirstLast( {7, 6 ,9 ,12} ) | { 12 , 6 , 9, 7} |

**public String[] swapFirstMiddle(String[] strs)**

Description:This method returns a new version of the array with the first and middle elements of`strs`

swapped.

Method Call |
return value/output |

swapFirstMiddle( {“a”,”b”,”c” } ) | { “b”, “a”, “c”} |

swapFirstMiddle( { “zoo”,”foo”, “xoo”} ) | { “foo”,”zoo”, “xoo”} |

Loops

**public void printEveryOther(int[] nums)**

Description:This method prints every other element of`nums`

on new lines .

Method Call |
return value/output |

printEveryOther( {1 , 2 , 3 , 4 } ) |
1 3 |

printEveryOther( {13 , 42 , 33 , 44 , 52} ) |
13 33 52 |

**public int sum(int[] nums )**

Description:This method returns the sum of`nums`

..

Method Call |
return value/output |

sum( { 2 , 8 }) | 10 ie 2 + 8 |

sum( { 2 , 8 , 4 } ) | 14 ie (2 + 8 + 4 ) |

**public int sumOdds(int[] nums )**

Description:This method returns the sum of all the odd element of`nums`

.

Method Call |
return value/output |

sumOdds( { 5 , 2, 4 , 6 , 7 } ) |
12 ( ie 5 + 7 ) |

sumOdds( { 13 , 3, 2, 6 , 7 } ) |
23 |

**public double mean(int[] nums )**

Description:This method returns the mean of`nums`

. Pay close attention to the second sample call and make sure you get “5.25“

Method Call |
return value/output |

mean( { 2 , 8 }) | 5.0 ie (2+8)/2 |

mean( { 2 , 8 , 4 , 7 } ) | 5.25 ie (2+8+4+7)/4 |

**public double largest(double[] nums )**

Description:This method returns the element of`nums`

with the greatest value. Make sure that you test out the second call and get ‘-2‘.

Method Call |
return value/output |

largest( { 2.6 , 8.2, 5.2}) | 8.2 |

largest( { -2,-11, -4} ) | -2 |

**public int sumEveryN(int[] nums, int n)**

Description:This method returns the sum of every`n`

elements of`num`

s..

Method Call |
return value/output |

sumEveryN( {1 , 2 , 3 , 4 }, 2 ) |
4( ie 1 +3) |

sumEveryN( {13 , 42, 15, 33 , 44 , 16 , 52} ,3) |
98 ( ie 13 + 33+ 52) |

***public int secondSmallest(int[] nums )**

Description:This method returns the element of`nums`

with the second smallest value.

Method Call |
return value/output |

secondSmallest( { 2 , 18 , 22, 4 , 6 } ) | 4 |

secondSmallest( { 3 , 7 , 15 , 1 ,101} ) | 3 |

**** boolean isPalindromic(int[] nums)**

Description:This method returns true if the elements of`nums`

are a palindrome..

Method Call |
return value/output |

isPalindromic(( { 5 , 2, 7 , 2 , 5} ) | true |

isPalindromic( { 5 , 2, 7 , 3 , 5} )) |
false |

isPalindromic(( { 1 , 2, 1} ) | true |

**int[] add(int[] num1, int[] num2, int base) throws ArithmeticException**

**@precondition**

`1 < base < 11`

**@precondition**

**num1**.length = 5 and **num2.length = 5**

**@postcondition:**the returned array has 5 elements representing the sum or an ArithmeticException is thrown

Description:This method attempts to replicate addition. Consider both num1 and num2 represent the five digits of a number. Each element in the array stores one of the digits. For instance, the number 143 would be represented as {0,0,1,4,3 }. Numbers can be in any base between 2 and 10 inclusive , and the number 10110_{2}in binary would appear in an arrays as : {1, 0, 1 , 1, 0 } . Let’s assume the numbers are positive.You should return an array representing the digits of the sum of num1 and num2. You may not do any math besides addition. You may not use any external libraries for any math or base conversions.Ifthe number of digits in thesum exceeds the maximum number of digits (5) , you should throw an arithmetic exception as shown in the code below:

12 if(overFlowAdditionOccurred)throw new ArithmeticException("Addition Overflow Error");

**Note:** You may not use any kind of helper or utility methods that are built into pre-defined Java classes for converting numbers between bases. Only use techniques taught in this class. What you have to do is reproduce the additional algorithm and find a way to carry digits , programmatically.

Method Call |
return value/output |

add( {0,0,0 ,4,2},{0,0,0,5,1}, 10) | {0, 0, 0, 9, 3} ie (42 + 51 = 93) |

add( {0, 0, 0 ,7,2},{0,0,0,5,1}, 10) | {0, 0 , 1 , 2, 3} ie (72 + 51 = 123) |

add( {0, 0 , 0 , 1 , 1}, { 0 , 0 , 0 , 1 }, 2) | {0, 0 , 1 , 0 , 0} ie ( 11_{2} + 1_{2}= 100_{2} ) |