Array (陣列) 1:		July 2, 2011
===============

1. int a,b,c,d,e;	// 一般宣告變數方式
   a = 1;
   b = 2;
   scanf("%d %d %d %d", &a, &b, &c, &d);
   d = a+b+c;

   what if? int a,b,...,aa,ab,...,zx,zy,zz;


2. int a[1000];		// 以陣列宣告變數方式
   a[0] = 1;
   a[1] = 2;
   a[999] = 66;
   scanf("%d %d %d %d", &a[0],&a[1],&a[2],&a[3]);

   for(i=0;i<1000;i++)
       scanf("%d", &a[i]);	// 輸入1000個整數

   for(i=0;i<1000;i++)
       printf("%d\n", a[i]);	// 輸出1000個整數

   for(i=0;i<1000;i++)
       a[i]=i;			// a[0]=0; ... a[999]=999;

   for(i=0;i<1000;i++)
       a[i]=1000-i;		// a[0]=1000; a[1]=999, ... a[999]=1;

   for(i=0;i<1000;i++)
       a[i]=2*i+1;		// a[0]=1; a[1]=3; ... a[999]=1999;

3. char name[40][20];
   strcpy(name[0],"chan tai man");	// string copy

   scanf("%s",name[2]);
   gets(name[2]);

   for(i=0;i<40;i++) gets(name[i]);	// 輸入40個名字
   for(i=0;i<40;i++) printf(name[i]);	// 輸出40個名字
   for(i=0;i<40;i++) puts(name[i]);	// 輸出40個名字

4. int score[40], sum=0;	// 40個分數
   score[12] = 50;
   for(i=0;i<40;i++) scanf("%d",&score[i]);

   sum = score[0] + score[1] + ... + score[39];

   for(i=0;i<40;i++) sum = sum+score[i];	// 簡潔
   avg = sum/40;

5. char grade[40];	// 40個等級
   grade[0] = 'A';
   grade[1] = 'B';

   for(i=0;i<40;i++){
       if(score[i]>=50) grade[i]="A";
       else grade[i] = "B";
   }
   for(i=0;i<40;i++){
       if(score[i]<=20) grade[i]="E";
       else if(score[i]<=40) grade[i]="D";
       else if(score[i]<=60) grade[i]="C";
       else if(score[i]<=80) grade[i]="B";
       else grade[i]="A";
   }

   for(i=0;i<40;i++)	// 列印姓名、分數、等級
      printf("%3d %-20s %5d %c \n", i, name[i], score[i], grade[i]);

6. float xcoordinate[10], ycoordinate[10];	// x,y座標
   xcoordinate[0] = -4.0;
   ycoordinate[0] = 5.5;

7. use of array 陣列的應用:
   int mm;
   char monthname[13][4]={"x",
		"Jan","Feb","Mar","Apr","May","Jun",
		"Jul","Aug","Sep","Oct","Nov","Dec"};
   while(1){
      scanf("%d",&mm);
      printf("%s\n", monthname[mm]);
   }

8. homework: literal.c	// 文字
   arrays:
         1. units[1-19]		// 個位
            units[1]  <-- "one";
            units[2]  <-- "two";
            ...
            units[19] <-- "nineteen"

         2. tens[2-9]		// 十位
            tens[2] <-- "twenty";
            tens[3] <-- "thirty";
            ...
            tens[9] <-- "ninety"

    sample output screen 輸出畫面:
           Q: Enter a number (1-99) :   34
           A: thirty four

    algorithm算法:
           1. prepare arrays 準備兩個陣列 units[] and tens[]
           2. ask user for input 輸入 (n)
           3. if n<20 then output 輸出文字 words stored in array units[]
           4. else break down 分柝 n into
                 unit digit個位 and tens digit十位
                 using function mod(%) and div(/)
              and output appropriate 輸出適當文字 words on the screen

  literals文字:
     1-10	one two three four five six seven eight nine ten
    11-15	eleven twelve thirteen fourteen fifteen
    16-19	sixteen seventeen eighteen nineteen
    20-90	twenty thirty forty fifty sixty seventy eighty ninety


For-loop:重溫
=========
1. sum of first n integers 首n個整數的和
   int i, sum=0;
   for(i=1;i<=10;i++) sum = sum+i;

2. factorial of n: 首n個整數的積
   int i, factorial=1;
   for(i=1;i<=10;i++) factorial = factorial*i;

3. alphabets: 字母
   char ch;
   for(ch=65;ch<=90;ch++)
      printf("%d %c\n", ch,ch);

   for(ch='a';ch<='z';ch++)
      printf("%d %c\n", ch,ch);

4. display triangle: 三角形
   for(i=0;i<5;i++){
      for(j=0;j<i;j++)
         printf("*");
      puts("");
   }


Array (陣列) 2:
===============
1. float a[10];
   a[0] = 10.0;
   scanf("%f", &a[1]);		// 例如: 輸入20

   a[2] = a[0]*5 + a[1];	// a[2] = 10.0*5 + 20 = 70
   printf("a[3]=%d\n", a[3]);

   for(i=0;i<10;i++)
       a[i]=10-i;		// a[0]=10; a[1]=9; ... a[9]=1;
   for(i=0;i<10;i++)
       printf("%.0f\n", a[i]);

   sum = 0;
   for(i=0;i<10;i++)
       sum = sum+a[i];		// sum = a[0]+a[1]+a[2]+...+a[9];

2. factorial (=1x2x3x...x10)
   int product=1;
   for(i=1;i<=10;i++)
       product = product*i;	// product = 1*2*3*...*10;

3. shift left 左移/上移
   a[0] = a[1];
   a[1] = a[2];
   a[2] = a[3];

   for(i=0;i<9;i++) a[i] = a[i+1];

4. shift right 右移/下移
   a[1] = a[0];
   a[2] = a[1];
   a[3] = a[2];

   for(i=9;i>0;i--) a[i] = a[i-1];	當i=9, a[9]=a[8];

   what if?
   for(i=0;i<9;i++) a[i+1] = a[i];

5. swapping x,y 互換
   int x=100, y=50, t;

   t = x;
   x = y;
   y = t;

6. swapping a[0],a[9] 互換
   int a[10], t;

   t    = a[0];
   a[0] = a[9];
   a[9] = t;

7. reverse 反轉/倒轉(數值)
   for(i=0;i<5;i++){
      t      = a[i];
      a[i]   = a[9-i];
      a[9-i] = t;
   }

   what if? int a[400];

8. reverse 反轉/倒轉(列印)
   for(i=0;i<10;i++)
       printf("%d\n", a[9-i]);

   for(i=9;i>=0;i--)
       printf("%d\n", a[i]);


9. 陣列的應用
(a) char animals[12][3]={"猴","雞","狗","豬","鼠","牛",
			"虎","兔","龍","蛇","馬","羊"};
	i=0;
	printf("%s\n", animals[i]);


(b) char monthname[13][4]={"x","Jan","Feb","Mar","Apr","May","Jun",
			"Jul","Aug","Sep","Oct","Nov","Dec"};
	mm=9;
	printf("%s\n", monthname[mm]);


(c) char cdow[7][4]={"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};

(d) char cnum[11][3]={"○","一","二","三","四","五","六","七","八","九","十"};

	n=24;
	printf("%s十%s\n", cnum[?],cnum[?]);


(e) int maxday[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};

	do{
		printf("Enter mm,dd  ");
		scanf("%i%i",&mm,&dd);
	}while(mm<1 || mm>12 || dd<1 || dd>31);


(f) int zday[13]={0,20,19,21,21,21,22,23,24,23,23,22,22};

(g) char zodiac[13][5]={"x","水瓶","雙魚","白羊","金牛","雙子","巨蟹",
			"獅子","處女","天秤","天蠍","人馬","山羊"};

	Z = mm;
	if(dd<...
	...
	printf("zodiac = %s\n", zodiac[z]);

(10) More examples

(a)
int maxday[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
maxday[0] = 0;
maxday[1] = 31;  maxday[3] = 31;  maxday[ 5] = 31;
maxday[2] = 28;
maxday[4] = 30;  maxday[6] = 30;  maxday[ 9] = 30;  maxday[11] = 30;
maxday[7] = 31;  maxday[8] = 31;  maxday[10] = 31;  maxday[12] = 31;

(b)
int mark[40] = {0};
mark[0]=100;
mark[1]=95;
...
mark[39]=50;

(c)
int card[52];
card[ 0] = 0;   card[ 1] = 1;   card[ 2] = 2;   ... card[12] = 12;
card[13] = 13;  card[14] = 14;  card[15] = 15;  ... card[25] = 25;
card[26] = 26;  card[27] = 27;  card[28] = 28;  ... card[38] = 38;
card[39] = 39;  card[40] = 40;  card[41] = 41;  ... card[51] = 51;

(d) mark6
int num[40]={0};
num[0] = 0;
num[1] = 0;
...
num[49] = 1;

(e)
int freq[26]={0};
freq[0] = 0;
freq[1] = 25;
freq[2] = 236;
freq[3] = 926;
freq[4] = 2730;
freq[5] = 1371;

(f) money note
int note[9] = {1000,500,100,50,20,10,5,2,1};
note[0] = 1000;	note[3] = 50;	note[6] = 5;
note[1] = 500;	note[4] = 20;	note[7] = 2;
note[2] = 100;	note[5] = 10;	note[8] = 1;

(g)
int num[13] = {1000,900,500,400, 100,90,50,40, 10,9,5,4,1};
num[0] = 1000;	num[4] = 100;	num[ 8] = 10;
num[1] = 900;	num[5] = 90;	num[ 9] = 9;
num[2] = 500;	num[6] = 50;	num[10] = 5;
num[3] = 400;	num[7] = 40;	num[11] = 4;	num[12] = 1;

(h)
char roman[13][3]
= {"M","CM","D","CD", "C","XC","L","XL", "X","IX","V","IV","I"};
roman[0] ← "M" ;  roman[4] ← "C" ;  roman[ 8] ← "X";
roman[1] ← "CM";  roman[5] ← "XC";  roman[ 9] ← "IX";
roman[2] ← "D" ;  roman[6] ← "L" ;  roman[10] ← "V";
roman[3] ← "CD";  roman[7] ← "XL";  roman[11] ← "IV";  roman[12] ← "I";

(i)
char animals[12][3]
	= {"猴","雞","狗","豬","鼠","牛", "虎","兔","龍","蛇","馬","羊"};
animals[0] ← "猴"	animals[ 6] ← "虎"
animals[1] ← "雞"	animals[ 7] ← "兔"
animals[2] ← "狗"	animals[ 8] ← "龍"
animals[3] ← "豬"	animals[ 9] ← "蛇"
animals[4] ← "鼠"	animals[10] ← "馬"
animals[5] ← "牛"	animals[11] ← "羊"

(j) 2-D array
int num[3][4];
num[0][0] = 88;  num[0][1] = 78;  num[0][2] = 68;  num[0][3] = 58;
num[1][0] = 77;  num[1][1] = 48;  num[1][2] = 64;  num[1][3] = 82;
num[2][0] = 66;  num[2][1] = 28;  num[2][2] = 61;  num[2][3] = 85;

(k)
int rowTL[3], colTL[4];
rowTL[0]=10;	colTL[0]=34;
rowTL[1]=20;	colTL[1]=45;
rowTL[2]=30;	colTL[2]=56;
		colTL[3]=67;
(l)
char cjcode[13000][6];	// 倉頡碼
cjcode[0] ← "M"
cjcode[1] ← "MN"
cjcode[5] ← "MMM"
...
cjcode[12999] ← "SMR"

(m)
char cword[13000][3];	// 中文字
cword[0] ← "一"
cword[1] ← "丁"
cword[5] ← "三"
...
cword[12999] ← "司"

(n)
char name[40][10];
name[0] ← "Chan TM"
name[1] ← "Chen ST"
name[2] ← "陳七"
...

(o)
char monthname[13]={"",
	"Jan","Feb","Mar","Apr","May","Jun",
	"Jul","Aug","Sep","Oct","Nov","Dec"};
monthname[1] ← "Jan"
monthname[2] ← "Feb"
...
monthname[12] ← "Dec"

(p)
char units[20][10] = {"","one","two","three","four","five",
	"six","seven","eight","nine","ten",
	"eleven","twelve","thirteen","fourteen","fifteen",
	"sixteen","seventeen","eighteen","nineteen"};
units[1] ← "one"
units[2] ← "two"
units[3] ← "three"
...
units[19] ← "nineteen"

(q)
char tens[10][8] = {"","ten","twenty","thirty","forty",
	"fifty","sixty","seventy","eighty","ninety"};
tens[1] ← "ten"
tens[2] ← "twenty"
tens[3] ← "thirty"
...
tens[9] ← "ninety"

(r)
char cdow[7][4]
	={"Sun","Mon","Tue","Wed","Thu","Fri","Sat"}; 
cdow[0] ← "Sun"
cdow[1] ← "Mon"
cdow[2] ← "Tue"
...
cdow[6] ← "Sat"

(s)
char cnum[10][3]
	={"○","一","二","三","四","五","六","七","八","九"};
cnum[0] ← "○"
cnum[1] ← "一"
cnum[2] ← "二"
...
cnum[9] ← "九"

(t)
char zodiac[13][5]={"山羊",
	"水瓶","雙魚","白羊","金牛","雙子","巨蟹",
	"獅子","處女","天秤","天蠍","人馬","山羊"}; 

int zday[13]={0,
	20,19,21,21,21,22,23,24,23,23,22,22};

(u)
int count[10]={0};

(v)
int prime[101]={0};
prime[1]=0;	// not prime
prime[2]=1;
prime[3]=1;
prime[4]=0;
...

(w)
#define MAX 13
int st[MAX]={0,2,3,3,4,3,2,4,6,3,5,2,4};
int stnTime[MAX][MAX];

char stnName[MAX][3]={		// 車站名稱
	"TT","KN","MK","KT","TW","ST","FT",
	"UV","TP","WO","FL","SS","LW"};

char stnName[14][7]={"",
	"尖東","紅磡","旺角","九龍塘","大圍",
	"沙田","火炭","大學","大埔墟","太和",
	"粉嶺","上水","羅湖"};

int score[40][6];	// 40 students x 6 subjects
score[0][0] = 100;	// student 0, subject 0
...
score[0][5] = 50;	// student 0, subject 5

score[39][0] = 99;	// student 39, subject 0
...
score[39][5] = 88;	// student 39, subject 5

char grade[40][6];
grade[0][0]='A';	grade[39][0]='A';
...
grade[0][5]='D';	grade[39][5]='B';

(x)
magicSquare[][]
gameboard[][]

sudoku
game of life
chess

tictactoe[][]