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Introduction

  • Welcome back. Congratulations on your admission.

This subject is a selection of the best exercises of the piscine-go. This selection was made to get back smoothly to programming in go after the pause period. All the exercises have to be done and they must all pass each and every tests.

The goal of this project is to realize what you know and what you still need to practice on. We strongly advise you to resist the temptation of looking at your old repository.

To really learn programming, you must practice programming, so copy and pasting some old code will not help the learning process.

One more detail. This time the project will be corrected by auditors. The auditors will be others students and you will be an auditor as well.

We advise you to create your own tests for yourself and for when you will correct your students.


atoi

Allowed functions

  • "--cast"

Instructions

  • Write a function that simulates the behaviour of the Atoi function in Go. Atoi transforms a number represented as a string in a number represented as an int.

  • Atoi returns 0 if the string is not considered as a valid number. For this exercise non-valid string chains will be tested. Some will contain non-digits characters.

  • For this exercise the handling of the signs + or - does have to be taken into account.

  • This function will only have to return the int. For this exercise the error result of atoi is not required.

Expected function

func Atoi(s string) int {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	s := "12345"
	s2 := "0000000012345"
	s3 := "012 345"
	s4 := "Hello World!"
	s5 := "+1234"
	s6 := "-1234"
	s7 := "++1234"
	s8 := "--1234"

	n := student.Atoi(s)
	n2 := student.Atoi(s2)
	n3 := student.Atoi(s3)
	n4 := student.Atoi(s4)
	n5 := student.Atoi(s5)
	n6 := student.Atoi(s6)
	n7 := student.Atoi(s7)
	n8 := student.Atoi(s8)

	fmt.Println(n)
	fmt.Println(n2)
	fmt.Println(n3)
	fmt.Println(n4)
	fmt.Println(n5)
	fmt.Println(n6)
	fmt.Println(n7)
	fmt.Println(n8)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
12345
12345
0
0
1234
-1234
0
0
student@ubuntu:~/[[ROOT]]/test$

recursivepower

Allowed functions

  • "--cast"

Instructions

Write an recursive function that returns the power of the int passed as parameter.

Negative powers will return 0. Overflows do not have to be dealt with.

for is forbidden for this exercise.

Expected function

func RecursivePower(nb int, power int) int {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	arg1 := 4
	arg2 := 3
	fmt.Println(student.RecursivePower(arg1, arg2))
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
64
student@ubuntu:~/[[ROOT]]/test$

printcombn

Allowed functions

  • "--cast"
  • "github.com/01-edu/z01.PrintRune"

Instructions

  • Write a function that prints all possible combinations of n different digits in ascending order.

  • n will be defined as : 0 < n < 10

below are your references for the printing format expected.

  • (for n = 1) '0, 1, 2, 3, ...8, 9'

  • (for n = 3) '012, 013, 014, 015, 016, 017, 018, 019, 023,...689, 789'

Expected function

func PrintCombN(n int) {

}

Usage

Here is a possible program to test your function :

package main

import student ".."

func main() {
	student.PrintCombN(1)
	student.PrintCombN(3)
	student.PrintCombN(9)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
012, 013, 014, 015, 016, 017, 018, ... 679, 689, 789
012345678, 012345679, ..., 123456789
student@ubuntu:~/[[ROOT]]/test$

printnbrbase

Allowed functions

  • "--cast"
  • "github.com/01-edu/z01.PrintRune"

Instructions

Write a function that prints an int in a string base passed in parameters.

If the base is not valid, the function prints NV (Not Valid):

Validity rules for a base :

  • A base must contain at least 2 characters.
  • Each character of a base must be unique.
  • A base should not contain + or - characters.

The function has to manage negative numbers. (as shown in the example)

Expected function

func PrintNbrBase(nbr int, base string) {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	"github.com/01-edu/z01"
	student ".."
)

func main() {
	student.PrintNbrBase(125, "0123456789")
	z01.PrintRune('\n')
	student.PrintNbrBase(-125, "01")
	z01.PrintRune('\n')
	student.PrintNbrBase(125, "0123456789ABCDEF")
	z01.PrintRune('\n')
	student.PrintNbrBase(-125, "choumi")
	z01.PrintRune('\n')
	student.PrintNbrBase(125, "aa")
	z01.PrintRune('\n')
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
125
-1111101
7D
-uoi
NV
student@ubuntu:~/[[ROOT]]/test$

doop

Allowed functions

  • "--cast"
  • "github.com/01-edu/z01.PrintRune"
  • "os.*"
  • ".."

Instructions

Write a program that is called doop.

The program has to be used with three arguments:

  • A value
  • An operator
  • Another value

You should use int64.

The following operators are considered valid: +, -, /, *, %.

In case of an invalid operator or overflow the programs prints 0.

In case of an invalid number of arguments the program prints nothing.

The program has to handle the modulo and division operations by 0 as shown on the output examples below.

Usage

student@ubuntu:~/[[ROOT]]/test$ go build doop.go
student@ubuntu:~/[[ROOT]]/test$ ./doop
student@ubuntu:~/[[ROOT]]/test$ ./doop 1 + 1 | cat -e
2$
student@ubuntu:~/[[ROOT]]/test$ ./doop hello + 1 | cat -e
0$
student@ubuntu:~/[[ROOT]]/test$ ./doop 1 p 1 | cat -e
0$
student@ubuntu:~/[[ROOT]]/test$ ./doop 1 / 0 | cat -e
No division by 0$
student@ubuntu:~/[[ROOT]]/test$ ./doop 1 % 0 | cat -e
No modulo by 0$
student@ubuntu:~/[[ROOT]]/test$ ./doop 9223372036854775807 + 1
0
student@ubuntu:~/[[ROOT]]/test$ ./doop -9223372036854775809 - 3
0
student@ubuntu:~/[[ROOT]]/test$ ./doop 9223372036854775807 "*" 3
0
student@ubuntu:~/[[ROOT]]/test$ ./doop 1 "*" 1
1
student@ubuntu:~/[[ROOT]]/test$ ./doop 1 "*" -1
-1
student@ubuntu:~/[[ROOT]]/test$

atoibase

Allowed functions

  • "--cast"
  • "make"

Instructions

Write a function that takes a string number and its string base in parameters and returns its conversion as an int.

If the base or the string number is not valid it returns 0:

Validity rules for a base :

  • A base must contain at least 2 characters.
  • Each character of a base must be unique.
  • A base should not contain + or - characters.

Only valid string numbers will be tested.

The function does not have to manage negative numbers.

Expected function

func AtoiBase(s string, base string) int {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	fmt.Println(student.AtoiBase("125", "0123456789"))
	fmt.Println(student.AtoiBase("1111101", "01"))
	fmt.Println(student.AtoiBase("7D", "0123456789ABCDEF"))
	fmt.Println(student.AtoiBase("uoi", "choumi"))
	fmt.Println(student.AtoiBase("bbbbbab", "-ab"))
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
125
125
125
125
0
student@ubuntu:~/[[ROOT]]/test$

splitwhitespaces

Allowed functions

  • "--cast"
  • "make"

Instructions

Write a function that separates the words of a string and puts them in a string slice.

The separators are spaces, tabs and newlines.

Expected function

func SplitWhiteSpaces(str string) []string {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	str := "Hello how are you?"
	fmt.Println(student.SplitWhiteSpaces(str))
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
[Hello how are you?]
student@ubuntu:~/[[ROOT]]/test$

split

Allowed functions

  • "--cast"
  • "make"

Instructions

Write a function that simulates the behaviour of the strings.Split function in Go. strings.Split separates the words of a string and puts them in a string slice. The separators are the characters of the separator string given in parameter.

Expected function

func Split(s, sep string) []string {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	str := "HelloHAhowHAareHAyou?"
	fmt.Println(student.Split(str, "HA"))
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
[Hello how are you?]
student@ubuntu:~/[[ROOT]]/test$

convertbase

Allowed functions

  • "--cast"
  • ".."

Instructions

Write a function that returns the conversion of a string number from one string baseFrom to one string baseTo.

Only valid bases will be tested.

Negative numbers will not be tested.

Expected function

func ConvertBase(nbr, baseFrom, baseTo string) string {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	result := student.ConvertBase("101011", "01", "0123456789")
	fmt.Println(result)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
43
student@ubuntu:~/[[ROOT]]/test$

rotatevowels

Allowed functions

  • "os.*"
  • "--cast"
  • "github.com/01-edu/z01.PrintRune"
  • "make"

Instructions

Write a program that checks the arguments for vowels.

  • If the argument contains vowels (for this exercise y is not considered a vowel) the program has to "mirror" the position of the vowels in the argument (see the examples).
  • If the number of arguments is less than 1, the program display a new line ("\n").
  • If the arguments does not have any vowels, the program just prints the arguments.

Example of output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./rotatevowels "Hello World" | cat -e
Hollo Werld$
student@ubuntu:~/[[ROOT]]/test$ ./rotatevowels "HEllO World" "problem solved"
Hello Werld problom sOlvEd
student@ubuntu:~/[[ROOT]]/test$ ./rotatevowels "str" "shh" "psst"
str shh psst
student@ubuntu:~/[[ROOT]]/test$ ./rotatevowels "happy thoughts" "good luck"
huppy thooghts guod lack
student@ubuntu:~/[[ROOT]]/test$ ./rotatevowels "aEi" "Ou"
uOi Ea
student@ubuntu:~/[[ROOT]]/test$ ./rotatevowels

student@ubuntu:~/[[ROOT]]/test$

advancedsortwordarr

Allowed functions

  • ".."
  • "len"

Instructions

Write a function AdvancedSortWordArr that sorts a string slice, based on the function f passed in parameter.

Expected function

func AdvancedSortWordArr(a []string, f func(a, b string) int) {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {

	result := []string{"a", "A", "1", "b", "B", "2", "c", "C", "3"}
	student.AdvancedSortWordArr(result, student.Compare)

	fmt.Println(result)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
[1 2 3 A B C a b c]
student@ubuntu:~/[[ROOT]]/test$

cat

Allowed functions

  • "os.*"
  • "--cast"
  • "github.com/01-edu/z01.PrintRune"
  • ".."
  • "ioutil.*"
  • "io.*"

Instructions

Write a program that has the same behaviour as the system's cat command-line.

  • The options do not have to be handled.

  • If the program is called without arguments it should take the input and print it back (as shown with the "Hello" example below).

  • In the program folder create two files named quest8.txt and quest8T.txt.

  • Copy to the quest8.txt file the following sentence :

"Programming is a skill best acquired by practice and example rather than from books" by Alan Turing

  • Copy to the quest8T.txt file the following sentence :

"Alan Mathison Turing was an English mathematician, computer scientist, logician, cryptanalyst. Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer. Turing is widely considered to be the father of theoretical computer science and artificial intelligence."

  • In case of error the program should print the error.

  • The program must be submitted inside a folder named cat.

student@ubuntu:~/[[ROOT]]/cat$ go build
student@ubuntu:~/[[ROOT]]/cat$ ./cat abc
open abc: no such file or directory
student@ubuntu:~/[[ROOT]]/cat$ ./cat quest8.txt
"Programming is a skill best acquired by pratice and example rather than from books" by Alan Turing
student@ubuntu:~/[[ROOT]]/cat$ ./cat
Hello
Hello
^C
student@ubuntu:~/[[ROOT]]/cat$ ./cat quest8.txt quest8T.txt
"Programming is a skill best acquired by pratice and example rather than from books" by Alan Turing
"Alan Mathison Turing was an English mathematician, computer scientist, logician, cryptanalyst. Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer. Turing is widely considered to be the father of theoretical computer science and artificial intelligence."
student@ubuntu:~/[[ROOT]]/cat$

ztail

Allowed functions

  • "os.*"
  • "--cast"
  • "github.com/01-edu/z01.PrintRune"
  • "append"
  • "fmt.Printf"
  • ".."

Instructions

Write a program called ztail that has the same behaviour as the system command tail, but which takes at least one file as argument.

  • The only option to be handled is -c. This option will be used in all tests.

  • For this program the "os" package can be used.

  • For the program to pass the tests the convention for the return code of program in Unix systems should be followed.

  • Handle the errors and output the same error messages as tail.

  • For more information consult the man page for tail.

Note:

This program is gonna be tested against tail, be sure to check all the different error messages with different permutations of the arguments.


activebits

Allowed functions

  • "--cast"

Instructions

Write a function, ActiveBits, that returns the number of active bits (bits with the value 1) in the binary representation of an integer number.

Expected function

func ActiveBits(n int) uint {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	nbits := student.ActiveBits(7)
	fmt.Println(nbits)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
3
student@ubuntu:~/[[ROOT]]/test$

sortlistinsert

Allowed functions

  • "--no-array"

Instructions

Write a function SortListInsert that inserts data_ref in the linked list l while keeping the list sorted in ascending order.

  • During the tests the list passed as an argument will be already sorted.

Expected function and structure

func SortListInsert(l *NodeI, data_ref int) *NodeI{

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"

	student ".."
)

func PrintList(l *student.NodeI) {
	it := l
	for it != nil {
		fmt.Print(it.Data, " -> ")
		it = it.Next
	}
	fmt.Print(nil, "\n")
}

func listPushBack(l *student.NodeI, data int) *student.NodeI {
	n := &student.NodeI{Data: data}

	if l == nil {
		return n
	}
	iterator := l
	for iterator.Next != nil {
		iterator = iterator.Next
	}
	iterator.Next = n
	return l
}

func main() {

	var link *student.NodeI

	link = listPushBack(link, 1)
	link = listPushBack(link, 4)
	link = listPushBack(link, 9)

	PrintList(link)

	link = student.SortListInsert(link, -2)
	link = student.SortListInsert(link, 2)
	PrintList(link)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
1 -> 4 -> 9 -> <nil>
-2 -> 1 -> 2 -> 4 -> 9 -> <nil>
student@ubuntu:~/[[ROOT]]/test$

sortedlistmerge

Allowed functions

  • "--no-array"

Instructions

Write a function SortedListMerge that merges two lists n1 and n2 in ascending order.

  • During the tests n1 and n2 will already be initially sorted.

Expected function and structure

func SortedListMerge(n1 *NodeI, n2 *NodeI) *NodeI {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"

	student ".."
)

func PrintList(l *student.NodeI) {
	it := l
	for it != nil {
		fmt.Print(it.Data, " -> ")
		it = it.Next
	}
	fmt.Print(nil, "\n")
}

func listPushBack(l *student.NodeI, data int) *student.NodeI {
	n := &student.NodeI{Data: data}

	if l == nil {
		return n
	}
	iterator := l
	for iterator.Next != nil {
		iterator = iterator.Next
	}
	iterator.Next = n
	return l
}

func main() {
	var link *student.NodeI
	var link2 *student.NodeI

	link = listPushBack(link, 3)
	link = listPushBack(link, 5)
	link = listPushBack(link, 7)

	link2 = listPushBack(link2, -2)
	link2 = listPushBack(link2, 9)

	PrintList(student.SortedListMerge(link2, link))
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
-2 -> 3 -> 5 -> 7 -> 9 -> <nil>
student@ubuntu:~/[[ROOT]]/test$

listremoveif

Allowed functions

  • "--no-array"

Instructions

Write a function ListRemoveIf that removes all elements that are equal to the data_ref in the argument of the function.

Expected function and structure

type NodeL struct {
	Data interface{}
	Next *NodeL
}

type List struct {
	Head *NodeL
	Tail *NodeL
}

func ListRemoveIf(l *List, data_ref interface{}) {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"

	student ".."
)

func PrintList(l *student.List) {
	it := l.Head
	for it != nil {
		fmt.Print(it.Data, " -> ")
		it = it.Next
	}

	fmt.Print(nil, "\n")
}

func main() {
	link := &student.List{}
	link2 := &student.List{}

	fmt.Println("----normal state----")
	student.ListPushBack(link2, 1)
	PrintList(link2)
	student.ListRemoveIf(link2, 1)
	fmt.Println("------answer-----")
	PrintList(link2)
	fmt.Println()

	fmt.Println("----normal state----")
	student.ListPushBack(link, 1)
	student.ListPushBack(link, "Hello")
	student.ListPushBack(link, 1)
	student.ListPushBack(link, "There")
	student.ListPushBack(link, 1)
	student.ListPushBack(link, 1)
	student.ListPushBack(link, "How")
	student.ListPushBack(link, 1)
	student.ListPushBack(link, "are")
	student.ListPushBack(link, "you")
	student.ListPushBack(link, 1)
	PrintList(link)

	student.ListRemoveIf(link, 1)
	fmt.Println("------answer-----")
	PrintList(link)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
----normal state----
1 -> <nil>
------answer-----
<nil>

----normal state----
1 -> Hello -> 1 -> There -> 1 -> 1 -> How -> 1 -> are -> you -> 1 -> <nil>
------answer-----
Hello -> There -> How -> are -> you -> <nil>
student@ubuntu:~/[[ROOT]]/test$

btreetransplant

Instructions

In order to move subtrees around within the binary search tree, write a function, BTreeTransplant, which replaces the subtree started by node with the node rplc in the tree given by root.

Expected function

func BTreeTransplant(root, node, rplc *TreeNode) *TreeNode {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	root := &student.TreeNode{Data: "4"}
	student.BTreeInsertData(root, "1")
	student.BTreeInsertData(root, "7")
	student.BTreeInsertData(root, "5")
	node := student.BTreeSearchItem(root, "1")
	replacement := &student.TreeNode{Data: "3"}
	root = student.BTreeTransplant(root, node, replacement)
	student.BTreeApplyInorder(root, fmt.Println)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
3
4
5
7
student@ubuntu:~/[[ROOT]]/test$

btreeapplybylevel

Instructions

Write a function, BTreeApplyByLevel, that applies the function given by fn to each node of the tree given by root.

Expected function

func BTreeApplyByLevel(root *TreeNode, f func(...interface{}) (int, error))  {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	root := &student.TreeNode{Data: "4"}
	student.BTreeInsertData(root, "1")
	student.BTreeInsertData(root, "7")
	student.BTreeInsertData(root, "5")
	student.BTreeApplyByLevel(root, fmt.Println)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
4
1
7
5
student@ubuntu:~/[[ROOT]]/test$

btreedeletenode

Instructions

Write a function, BTreeDeleteNode, that deletes node from the tree given by root.

The resulting tree should still follow the binary search tree rules.

Expected function

func BTreeDeleteNode(root, node *TreeNode) *TreeNode {

}

Usage

Here is a possible program to test your function :

package main

import (
	"fmt"
	student ".."
)

func main() {
	root := &student.TreeNode{Data: "4"}
	student.BTreeInsertData(root, "1")
	student.BTreeInsertData(root, "7")
	student.BTreeInsertData(root, "5")
	node := student.BTreeSearchItem(root, "4")
	fmt.Println("Before delete:")
	student.BTreeApplyInorder(root, fmt.Println)
	root = student.BTreeDeleteNode(root, node)
	fmt.Println("After delete:")
	student.BTreeApplyInorder(root, fmt.Println)
}

And its output :

student@ubuntu:~/[[ROOT]]/test$ go build
student@ubuntu:~/[[ROOT]]/test$ ./test
Before delete:
1
4
5
7
After delete:
1
5
7
student@ubuntu:~/[[ROOT]]/test$