計算機程式 2020 fall
===
###### tags: `計算機程式`

[TOC]
## WEEK 1
### 1-2 DEC->BIN

#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
    int num = 0;                            //param for DEC
    int bin_counter = 0;                    //param to count
    int bin[100]={0};                       //array to save BIN value
    cin >> num;                               //input number
    if (num == 0)                           //deal with number if it's zero
        bin_counter = 1;
    else
    {
        for(bin_counter = 0 ; num > 0 ; bin_counter++ )    //break if num greater than zero , it means it can't be devided by 2 anymore
        {
            bin[bin_counter] = num % 2;       //get r
            num /= 2;                       // num = num/2;
        }
    }
    for (int j = bin_counter - 1; j >= 0; j--)      //print bin value inversely
        cout << bin[j] << " ";
    system("paunse");
    return 0;
}

>[name=逸男]

## WEEK 2
### 2-1 Calendar

#include <cstdlib>
#include <iostream>

using namespace std;

int main(void){
    int month, date, output=0;
    int days[] = {31, 29 ,31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    cout << "Please input month and date" << endl << "month: ";
    cin >> month;
    cout << "date: ";
    cin >> date;

    if( month >= 1 && month <= 12 && date > 0 && date <= days[month-1] ){
        for(int i=0; i < month-1; i++){
            output += days[i];
        }
        output += date;
        cout << "output: " << output;

    }else{
        cout << "Your input is wrong. haha";
    }

    return 0;
}

>[name=D暉]

### 2-2 Sum

# include <iostream>
# include <cstdlib>
using namespace std;

void Sum(long long int &a, long long int &b); // declare the function with reference arguments

int main(void){
    int a, b;
    cin >> a >> b;
    Sum(a, b);            // call the function
    cout << a << endl;
    system("pause");
    return 0;
}

void Sum(long long int &a, long long int &b){
    a = a + b;            // save the result to a
}

>[name=吉他之神]

### 2-3 Sort

# include <iostream>

using namespace std;

void Sort(int &a, int &b){
    if ( b >  a ){
        int tmp = a ;
        a = b;
        b = a;
    }
}

int main(void){
    int a, b;
    cin >> a >> b;
    Sort(a, b);            // call the function
    cout << a << " " << b << endl;
}

>[name=大神]

## WEEK 3

### 3-1 randomly choose 4 different numbers

# include <iostream>
# include <cstdlib>
# include <ctime>

using namespace std;

# define NUMBER_OF_DIFFFERENT_DIGITS 4	    // can be customized.

int main(void){
    srand(time(NULL));			    // set the random seed.
    int check[10] = {0};		    // check whether the digit is exist. 1 means exist, 0 means not.
    int number;
    for (int i = 0; i < NUMBER_OF_DIFFFERENT_DIGITS; i++){
	if (i == 0){			    // first digit can not be zero.
	    number = rand() % 9 + 1;	    // number within 1~9.
	}
	else{
	    number = rand() % 10;	    // number within 0~9.
	    while (check[number] != 0){	    // while number is exist then randomly generate again.
		number = rand() % 10;
	    }
	}
	check[number] = 1;		    // mark the number to prevent using again.
	cout << number;
    }
    cout << "\n";
    return 0;
}

>[name=吉他之神]

## WEEK 4

### 4-3 encoding

#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;

int main(){
    string str;
    int num;
    cin >> str;
    cin >> num;
    for (int i=0 ;i<str.length();i++)
        cout <<(char)(str[i] + num);
}

# include <iostream>
# include <cmath>

using namespace std;

void print_log(int num){
    cout << log10(num) << endl;  // call log10 function in <cmath> library
}

int main(void){
    int num;
    cin >> num;
    print_log(num);             // call self-defined function
    return 0;
}

>[name=神宗翰]

### 4-2 power

#include <iostream>
float pow(const double a,int b){
    float data=1;
    for(int i = 0;i<b;i++){
        data*=a;
    }
    return data;
}
int pow(const int a,int b){
    int data=1;
    for(int i = 0;i<b;i++){
        data*=a;
    }
    return data;
}
using namespace std;
int main(){
    int a, c;
    float b;
    cout << "輸入正整數:";
    cin  >> a ;
    cout << "輸入浮點數:";
    cin  >> b;
    cout << "輸入指數:";
    cin >> c;
    cout<<pow(a,c)<<endl;
    cout<<pow(b,c);
}

>[name=大哥翰]

### 4-3 Array and Random

#include <cstdlib>
#include <iostream>
#include <ctime>
using namespace std;


void find_max(int arr[3], int* Max){
    for (int i = 0; i < 3; i++){
        if (*Max < *(arr+i)){
            *Max = *(arr+i);
        }
    }
}

int main(void){
    int arr[3], Max=0;
    srand(time(NULL));
    for(auto offset = begin(arr); offset !=end(arr); offset++){
        *offset = rand()%10 + 1;
        cout << *offset << " ";
    }
    cout <<endl;

    find_max(arr, &Max);
    cout << Max << endl;
    return 0;
}

>[name=QQ龍的小夫]

## week 5

#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;

int main(){
    string str[3] ;
    int bill_line , flag;
    for(int i = 0 ;i<3;i++)
    {

        getline(cin,str[i]);
    }
    for(bill_line = 0 ;bill_line<3;bill_line++)
    {
            flag = str[bill_line].find("BILL");
            if (flag != -1 ){
                break;
            }
    }
    cout << bill_line+1 << endl;
    cout << flag <<endl;
}

>[name=NCRL狗]

## Midterm
### week1_rectangle

# include <iostream>

using namespace std;
int main(void){

    int length = 0, width = 0;

    cout << "length: " << endl;
    cin >> length;
    cout << "width: " << endl;
    cin >> width;

    for (int i=0; i < length; i++)
    {
        if (i == 0 || i == (length-1))
        {
            for (int j=0; j < width; j++) cout << "*";
            cout << endl;
        }
        else
        {
            for (int j=0; j < width; j++)
            {
                if (j == 0 || j == (width-1))
                {
                    cout << "*";
                }
                else
                {
                    cout << " ";
                }
            }
            cout << endl;
        }
    }

    return 0;
}

### week1_scorePassFailed

# include <iostream>

using namespace std;

typedef struct classes{
    int pass;
    int failed;
    classes()
    {
        pass = 0;
        failed = 0;
    }
}classes;

int main(void){
    int num = 5;
    int score[num];
    classes myClass;

    while (num--)
    {
        cin >> score[num];
        if (score[num] >= 60)
        {
            myClass.pass++;
        }else
            myClass.failed++;
    }

    cout << "pass: " << myClass.pass << endl;
    cout << "failed: " << myClass.failed;
}

### week1_Armstrong

# include <iostream>
# include <cmath>

using namespace std;

int count_digit(int num){
	if (num == 0) return 1;
	int digit = 0;
	while(num){
		digit++;
		num /= 10;
	}
	return digit;
}

int Armstrong(int num, int digit){
	int arr[digit], ans = 0;
	for (int i = 0; i < digit; i++){
		arr[i] = num % 10;
		num /= 10;
	}
	for (int i = 0; i < digit; i++){
		ans += pow(arr[i], digit);
	}
	return ans;
}

int main(void){
	int low, high, exist = 0;
	cin >> low >> high;
	for (int i = low; i < high; i++){
		int digit = count_digit(i);
		if (Armstrong(i, digit) == i) {
			cout << i << " ";
			exist = 1;
		}
	}
	if (exist == 0) cout << "none";
	cout << endl;		
	return 0;
}

### Week1 Simple substitution cipher

#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cstring>

using namespace std;

int main(){
    char map_array[27];
    char key[26];
    char plain[50];
    int flag = 0;
    int n = 0;

    cin>>key;
    strcpy (map_array,key);
    for(int i = strlen(map_array) ; i < 26 ; i++){
        do{
            flag = 0;
            for(int j = 0 ; j<i ; j++ ){
                if(('a'+ n) == map_array[j]){
                    n++;
                    flag = 1;
                    break;
                }
            }
        }while(flag == 1);
        map_array[i] = 'a'+n;
    }
    map_array[26] = '\0';
	cout <<map_array<<" "<<strlen(map_array)<<endl;
    cin >> plain;
    for(int i = 0 ;i<strlen(plain);i++){
        plain[i] = map_array[plain[i]-'a'];
    }
    cout << plain;
}

<!--
### week2_triangle

# include <iostream>

using namespace std;
int main(void){

    int width = 0;

    cout << "width: " << endl;
    cin >> width;

    for (int i=0; i <= (width-1)/2; i++)
    {
        for (int j=0; j < (width-1)/2 - i; j++)
        {
            cout << " ";
        }
        for (int j=0; j < 1 + 2*i; j++)
        {
            cout << "*";
        }
        cout << endl;
    }

    return 0;
}

### week2_student score

#include <iostream>
#include <cmath>

using namespace std;

typedef struct student{
    string id;
    double score = 0;
}student;

int main(void){
    int num = 5;
    student students[num];

    for (int i=0; i < num; i++)
    {
        cin >> students[i].id >> students[i].score;
        students[num].score = pow(students[num].score, 0.5)*10;
    }

    for (int i=0; i < num; i++)
    {
            cout << "id: " <<students[i].id << "\t score: " << students[i].score << endl;
    }

    return 0;
}

### Week2 bouble sort with student score

#include <iostream>

using namespace std;
typedef struct student{
    int student_id = 0;
    int score = 0;
}student;

void swap(student &a,student &b){
    student tmp ;
    tmp = a;
    a = b;
    b = tmp;
}

int main()
{
    int student_num = 0;
    cin>>student_num;
    student class_student[20];
    for(int i = 0 ; i<student_num ; i++){
        cin >> class_student[i].student_id;
        cin >> class_student[i].score;
    }

    for(int i=student_num ;  i>=0 ; i--){
        for(int j = 0 ; j<i-1 ; j++){
            if(class_student[j].score>class_student[j+1].score)
                swap(class_student[j+1],class_student[j]);
        }
    }
    for (int i = 0 ; i<student_num; i ++){
        cout << class_student[i].student_id<<" ";
    }
    return 0;
}

-->

## final

# include <iostream>
using namespace std;

void fun(int b){
    int a = 8;
    a++;
    b--;
}

int main(void){
    int a = 0;

    a += 1;
    a *= 2;
    --a;

    fun(a);
    cout << a << endl;  // a = ?

    return 0;
}

# include <iostream>
using namespace std;

int sum(int num1, int num2){
    return num1 + num2;
}

float sum(float num1, float num2){
    return num1 + num2;
}

int main(void){
    int a = 1, b = 2, ans1;
    float c = 1.1, d = 2.2, ans2;

    ans1 = sum(a, b);
    ans2 = sum(c, d);

    cout << ans1 << endl;   // ans1 = ?
    cout << ans2 << endl;   // ans2 = ?

    return 0;
}

# include <iostream>
using namespace std;

int sum(float num1, float num2){
    return num1 + num2;
}

float sum(float num1, float num2){
    return num1 + num2;
}

int main(void){
    int a = 1, b = 2, ans1;
    float c = 1.1, d = 2.2, ans2;

    ans1 = sum(a, b);
    ans2 = sum(c, d);

    cout << ans1 << endl;   // ans1 = ?
    cout << ans2 << endl;   // ans2 = ?

    return 0;
}


# include <iostream>
# include <cstdlib>
using namespace std;

int main(void)
{
    int a = 5, b = 10;
    int *ptr1, *ptr2;
    ptr1 = &a;
    ptr2 = &b;
    *ptr1 = 7;
    *ptr2 = 32;
    a = 17;
    ptr1 = ptr2;
    *ptr1 = 9;
    ptr1 = &a;
    a = 64;
    *ptr2 = *ptr1 + 5;
    ptr2 = &a;

    system("pause");
    return 0;
}

## week 12

#include <iostream>
#include <math.h>

using namespace std;

class shape
{
public:
    shape(string Obj, int Num_edges): obj(Obj), num_edges(Num_edges)
    {
        cout << "create a " << obj << endl;
        edges = new double[num_edges]; 
    }

    void set_edges(double* Edges)
    {
        edges = Edges;
    }

    double* get_edges() const
    {
        return edges;
    }

    int get_num_edges() const
    {
        return num_edges;
    }

    virtual double area() const = 0;
    
    ~shape()
    {
        delete [] edges;
    }

private:
    string obj;
    int num_edges;
    double* edges;
};

class triangle: public shape
{
public:
    triangle(double* Edges): shape("triangle", 3)
    {
        set_edges(Edges);
    }

    double area() const
    {
        double* ptr = get_edges();
        int num_edges = get_num_edges();
        return ptr[0]*ptr[1]/2;
    }
};

class circle: public shape
{
public:
    circle(double Edge): shape("circle", 1)
    {
        set_edges(&Edge);
        set_radius(Edge);
    }

    void set_radius(double edge)
    {
        radius = edge / (2 * M_PI);
    }

    double area() const
    {
        return radius*radius*M_PI;
    }

private:
    double radius;
};

int main()
{
    double tt_edges[] = {30.0, 40.0, 50.0};
    triangle tt(tt_edges);
    cout << tt.area() << endl;

    double cc_edge = 2*M_PI;
    circle cc(cc_edge);
    cout << cc.area() << endl;

    return 0;
}