readmes for the exrs of the exames

subjects/addprimesum.md

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+## addprimesum
+
+### Instructions
+
+Write a program that takes a positive integer as argument and displays the sum of all prime numbers inferior or equal to it followed by a newline.
+
+- If the number of arguments is not 1, or the argument is not a positive number, just display 0 followed by a newline.
+
+Example of output :
+
+```console
+student@ubuntu:~/piscine/test$ go build
+student@ubuntu:~/piscine/test$ ./test 5
+10
+student@ubuntu:~/piscine/test$ ./test 7
+17
+student@ubuntu:~/piscine/test$ ./test 57
+0
+student@ubuntu:~/piscine/test$
+```

subjects/doop.md

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+## switchcase
+
+### Instructions
+
+Write a program that takes three strings:
+
+- The first and the third one are representations of  base-10 signed integers that fit in an int.
+
+- The second one is an arithmetic operator chosen from: `+ - * / %`
+
+- The program must display the result of the requested arithmetic operation, followed by a newline. If the number of parameters is not 3, the program just displays a newline.
+
+- You can assume the string have no mistakes or extraneous characters. Negative numbers, in input or output, will have one and only one leading `-`. The result of the operation fits in an int.
+
+Example of output :
+
+```console
+student@ubuntu:~/piscine/test$ go build
+student@ubuntu:~/piscine/test$ ./test "123" "*" 456
+56088
+student@ubuntu:~/piscine/test$ ./test "9828" "/" 234
+42
+student@ubuntu:~/piscine/test$ ./test "10" "+" "-43"
+33
+student@ubuntu:~/piscine/test$ ./test
+
+student@ubuntu:~/piscine/test$
+```

subjects/printhex.md

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+## printhex
+
+### Instructions
+
+Write a program that takes a positive (or zero) number expressed in base 10, and displays it in base 16 (lowercase letters) followed by a newline.
+
+- If the number of parameters is not 1, the program displays a newline.
+
+Example of output :
+
+```console
+student@ubuntu:~/piscine/test$ go build
+student@ubuntu:~/piscine/test$ ./test "10"
+a
+student@ubuntu:~/piscine/test$ ./test "255"
+ff
+student@ubuntu:~/piscine/test$ ./test "5156454"
+4eae66
+student@ubuntu:~/piscine/test$
+
+student@ubuntu:~/piscine/
+```

subjects/range.md

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+## range
+
+### Instructions
+
+Write the following functions :
+
+```go
+func Range(start, end int) []int{
+
+}
+```
+
+It must allocate (with malloc()) an array of integers, fill it with consecutive values that begin at start and end at end (Including start and end !), then return a pointer to the first value of the array.
+
+Example of output :
+
+- With (1, 3) you will return an array containing 1, 2 and 3.
+- With (-1, 2) you will return an array containing -1, 0, 1 and 2.
+- With (0, 0) you will return an array containing 0.
+- With (0, -3) you will return an array containing 0, -1, -2 and -3.

subjects/sortlist.md

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+## sortlist
+
+### Instructions
+
+Write the following functions and its struture :
+
+```go
+type Node struct {
+	data int
+	next *node
+}
+
+func SortList(l *node, func cmp(a,b int) bool) *node{
+
+}
+```
+This function must sort the list given as a parameter, using the function `cmp` to select the order to apply, and returns a pointer to the first element of the sorted list.
+
+- Duplications must remain.
+
+- Inputs will always be consistet.
+
+- You must use the type `Node`
+
+- Functions passed as `cmp` will always return a boolean. If `a` and `b` are in the rigth order it returns `true`, otherwise it returns `false`.
+
+- For example, the following function used as cmp will sort the list in ascending order :
+
+```go
+func ascending(a, b int) {
+	if a <= b {
+		return true
+	} else {
+		return false
+	}
+}
+```

subjects/tabmult.md

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+## tabmult
+
+### Instructions
+
+Write a program that displays a number's multiplication table.
+
+- The parameter will always be a strictly positive number that fits in an int, and said number times 9 will also fit in an int.
+
+Example of output :
+
+```console
+student@ubuntu:~/piscine/test$ go build
+student@ubuntu:~/piscine/test$ ./test 9
+1 x 9 = 9
+2 x 9 = 18
+3 x 9 = 27
+4 x 9 = 36
+5 x 9 = 45
+6 x 9 = 54
+7 x 9 = 63
+8 x 9 = 72
+9 x 9 = 81
+student@ubuntu:~/piscine/test$ ./test 19
+1 x 19 = 19
+2 x 19 = 38
+3 x 19 = 57
+4 x 19 = 76
+5 x 19 = 95
+6 x 19 = 114
+7 x 19 = 133
+8 x 19 = 152
+9 x 19 = 171
+student@ubuntu:~/piscine/test$
+
+student@ubuntu:~/piscine/
+```