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# 计算概论代写 Introduction to Computing代写

2022-01-25 11:47 星期二 所属： CS代写 浏览：102

## CPSC111 – Introduction to Computing

An algorithm is a set of step-by-step procedure for accomplishing a task.

The word “algorithm” is derived from the ninth-century Muslim mathematician, Al-Khwarizmi who worked on “written processes to achieve some goal” [Abu Ja’far Muhammad ibn Musa Al-Khwarizmi]

The term “algebra” also derives from the term “al-jabr (means “restoring”, referring to the process of moving a subtracted quantity to the other side of an equation),” which he introduced.

Computer algorithms are central to computer science. They provide step-by step methods of computations that a machine can carry out.

Programmer’s job is to turn the algorithm into a program by adding details, testing procedures, and debugging or correcting errors.

We use algorithms every day. Recipes, instructions, and directions are all examples of algorithms that are not programs.

When you start your car, you follow a step-by-step procedure. The algorithm might look something like this:

### Algorithms   计算概论代写

An Algorithm is a series of steps required to solve a problem.

Example of your everyday life simple task algorithm; an algorithm for baking a cake might be:

Step1: Heat oven to 180 degrees Centigrade

Step2: Gather the ingredients

Step3: Mix the ingredients in a bowl

Step4: Pour the ingredients into a cake tin

Step5: Bake in the oven 20 minutes

Step6: Repeat

Step7: Bake in oven 5 minutes

Step8: Until cake cooked

Step9: Take cake out of oven and place on cake rack

We use algorithms in this way to help design the steps of a computer program.

Check your algorithm against the four criteria:

a. Un-ambiguous: When you read an algorithm, there should be no question about what should be done. If you understand cooking terms like “Gather the ingredients”, and “Baking a cake”, then you can probably follow most of this recipe.

b. Solves a problem: an algorithm should always present a solution to a particular problem. In our case, the problem must have been something like “Using these ingredients, make a cake.”

c. Legitimate input: In this example, “legitimate” ingredients include sugar, eggs, flour and butter.

d. Finite amount of time: once we start the algorithm, eventually it will finish at step 9

### Pseudocode  计算概论代写

Pseudo-code is an outline of a program written in a way that it can be easily converted into a computer programming language.

#### Examples of Algorithms

```Step 1 Start
Step 2 Prompt the user to enter the first integer
Step 3 Prompt the user to enter a second integer
Step 4 Compute the sum of the two user inputs
Step 5 Display the result
Step 6 Stop```

#### Others examples of Algorithms

Finding the largest of two numbers

```Step 1 Start
Step 3 If A > B, then BIG = A, otherwise BIG = B
Step 4 Write BIG
Step 5 Stop```

Finding the square and the cube of a number

```Step 1 Start
Step 2 Read value of N
Step 3 S = N * N
Step 4 C = S * N
Step 5 Write values of S, C
Step 6 Stop```

Finding average of any three numbers

```Step 1 Start
Step 2 Read values of X, Y, Z
Step 3 S = X + Y + Z
Step 4 A = S / 3
Step 5 Write value of A
Step 6 Stop```

### Questions  计算概论代写

The algorithms below have been written using pseudo-code. Can you say what each does?

Program 1

```1.start
6.stop```

Program 2

```1.start
5.unit_profit = juice_sale_price - juice_cost_price
6.total_profit = unit_profit x cans_sold
7.display total_profit
8.stop```

Program 3

```1.start
2.ask user for traffic light color
3.if color is red then
4.  display "STOP"
5.else if color is yellow then
6.  display "WAIT"
7.else
8.  display "PASS"
9.stop```

Program 4

```1.start
2.repeat 12 times
3.display "Happy Computing!"
4.end repeat
5.stop```

### Variables  计算概论代写

Variables are reserved memory locations to store values; when you create a variable you reserve some space in memory.

Based on the data type of a variable, the interpreter allocates memory and decides what can be stored in the reserved memory. Therefore, by assigning different data types to variables, you can store integers, decimals or characters in these variables

Python has some conventions for variable names. You can use any letter (lowercase or uppercase), the special character underscore “_” and every digit (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) provided you do not start with a digit.

Python variable names are case-sensitive, so counter and Counter are not the same variable.

The following list of words cannot be used as variable names. These are some reserved words (keywords) for Python. These keywords define the language rules and have special meanings in Python. Here is the list of all of them:

and, assert, break, class, continue, def, del, elif, else, except, exec, finally, for, from, global, if, import, in, is, lambda, not, or, pass, print, raise, return, try, while, yield

### Python Function Template  计算概论代写

```# Defining Functions

# def starts a function definition
# names of functions follow variable naming conventions

#A docstring is a string literal that occurs as the first statement in a function, module, class, or method definition.

def greeting():

""" A function for greeting people""" #docstring

print("Hello, World!")
print("From CPSC-111 Class")
print("At Alexander College in Burnaby, Canada")

greeting()```