伪代码编写练习可以使用网站：http://ibcomp.fis.edu/pseudocode/pcode.html
伪代码语法
循环逻辑：
loop i from ... to ...
TODO()
end loop
loop while (condition?)
TODO()
end loop
分支逻辑：
if (condition?) then
TODO()
else if (condition?) then
TODO()
else
TODO()
end if
数组管理：
arr = new array() // set a new array
arr = [..., ..., ...] //set values for the array
arr[...] //returns the value of a certain index
arr.Length() //returns the length of an array(for some reason this could not run on the above website)
集合管理：
coll = new collection() //set a new collection
coll.addItem(certain things) //add something to the collection
coll.getNext() //return the next value
coll.resetNext() //go back to the start of the collection
coll.hasNext() //returns a boolean value that indicates whether it has next item or not
coll.isEmpty() //returns a boolean value that indicates whether the collection is empty or not
栈管理：
// One thing to be remember, first in last out
stack = new stack() //set a new stack
stack.push(certain things) //push an item into the stack
stack.pop() //returns the last item of the stack
stack.isEmpty() //returns a boolean value that indicates whether the stack is empty or not
队列管理：
// Another thing to remember, first in first out
queue = new queue() //set a new queue
queue.enqueue(certain things) //put an item to the end of the queue
queue.dequeue() //delete and return the front item of the queue
queue.isEmpty() //returns a boolean value that indicates whether the queue is empty or not
流程图画法
Then use arrows to link the blocks.
简单代码的伪代码实现
The following codes are all based on arrays. Searching/Sorting other form of data set need to do simple modifications to the code.
Sequential Search
arr = [5, 6, 3, 4, 2, 7, 8, 1]
loop i from 0 to 7
if (arr[i] == 2) then
index = i
end if
end loop
output "The index of number 2 is: ", index
Binary Search
arr = [5, 6, 3, 4, 2, 7, 8, 1]
loop i from 0 to 6
min_idx = i
loop j from i+1 to 7
if arr[j] < arr[min_idx] then
min_idx = j
end if
end loop
if NOT(min_idx == i) then
TEMP = arr[min_idx]
arr[min_idx] = arr[i]
arr[i] = TEMP
end if
end loop
//Sort the array first since binary search is only applicable in ordered series
low = 0
high = 7
found = -1
loop while found = -1 AND low <= high
mid = div(low + high, 2)
if (arr[mid] = 8) then
found = mid
else if (arr[mid] < 8) then
low = mid + 1
else
high = mid - 1
end if
end loop
if found >= 0 then
output "The index of number 8 is: ", found
else
output "Number was not found"
end if
Bubble Sort
arr = [5, 6, 3, 4, 2, 7, 8, 1]
loop i from 0 to 6
loop j from 0 to 6-i
if arr[j] > arr[j+1] then
TEMP = arr[j+1]
arr[j+1] = arr[j]
arr[j] = TEMP
end if
end loop
end loop
loop i from 0 to 7
output arr[i]
end loop
Selection Sort
arr = [5, 6, 3, 4, 2, 7, 8, 1]
loop i from 0 to 6
min_idx = i
loop j from i+1 to 7
if arr[j] < arr[min_idx] then
min_idx = j
end if
end loop
if NOT(min_idx == i) then
TEMP = arr[min_idx]
arr[min_idx] = arr[i]
arr[i] = TEMP
end if
end loop
loop i from 0 to 7
output arr[i]
end loop
简单算法的流程图实现
Sequential Search
Binary Search
Bubble Sort
Selection Sort
