Programming & Language Telling the computer what to do 2005.04 綠園

Programming Why programming? Who program the program? For solving problem. Who program the program? The programmer is programming a program!

The Programmer Convert problem solutions into instruction for the computer. Coordination meetings with users, managers, system analysts, and with peers who evaluate your work.

The Programming Process defining the problem planning the solution coding the program testing the program, documenting the program.

Preparing a program for execution

The C Language 2004.09　綠園

History of C 西 元 1960 年 Algo 60 語 言 ( International Committe ) 西 元 1963 年 CPL 語 言 ( 劍 橋 與 倫 敦 大 學 ) 西 元 1966 年 BCPL 語 言 下 ( 劍橋大學 Martin Richards ) 西 元 1970 年 B 語 言 ( AT&T Ken Thompson ) 西 元 1972 年 C 語 言 ( AT&T Dennis Ritchie )

Program I : Hello, I am … #include <stdio.h> #include <stdlib.h> int main( ) { printf("Hello, I am Jenny!\n"); printf("This is output from my first program!\n"); system("PAUSE"); return 0; }

Program II : 5 + 7 = ? 執行結果 #include <stdio.h> #include <stdlib.h> int main() { int a, b, c; a = 5; b = 7; c = a + b; printf("%d + %d = %d\n", a, b, c); system("PAUSE"); return 0; } a b c 5 7 12 5+7

Program III : How old are you ? #include <stdio.h> 執行結果 #include <stdlib.h> int main( ) { int myage; myage = 16; printf("I am %d years old. \n", myage); printf("Next year, I will be %d years old. \n", myage+1); system("PAUSE"); return 0; }

How printf( ) work? printf("Hello"); printf("Hello\n"); printf("%d", b); printf("The temperature is "); printf(" degrees\n"); printf("The temperature is %d degrees\n", b); printf("%d + %d = %d\n", a, b, c);

資料型態 (character, 字元) char (integer, 整數) int (long integer, 長整數) long (short integer, 短整數) short (浮點數) float (倍精度浮點數) double 佔1 byte 佔4 bytes 佔2 bytes 佔8 bytes

How printf( ) work? int (整數) uses %d float (浮點數) uses %f char (字元) uses %c character strings(字串)use %s

變數 變數名稱要有意義，以增加程式的可讀性。（如num表數字、stud表學生人數） 變數名稱的限制： 不能使用Ｃ語言的關鍵字。 變數名稱的有效長度是前八位元。 可以是英文字母、數字或底線。 不能有空白字元。 第一個字元不能是數字。

計算BMI (一) 執行結果 已知：身高 height = 168; 體重 weight = 55; 求：BMI 運算式： BMI = weight / (height)2 （身高單位為公尺、體重單位為公斤。） BMI = weight/(height*height/10000); 輸出：你的 BMI 值為xx.xx (%.2f) 執行結果

Program IV : a + b = ? 執行結果 #include <stdio.h> #include <stdlib.h> int main() { int a, b, c; printf("Enter the first value:"); scanf("%d", &a); printf("Enter the second value:"); scanf("%d", &b); c = a + b; printf("%d + %d = %d\n", a, b, c); system("PAUSE"); return 0; }

Program V : How old are you ? #include <stdio.h> 執行結果 #include <stdlib.h> int main() { int yourage; printf("How old are you?"); scanf("%d", &yourage); printf("Next Year, you will be %d years old.\n", yourage+1); system("PAUSE"); return 0; }

How scanf() work? scanf("%d", &b); scanf("%d %d", &a, &b); int uses %d float uses %f char uses %c character strings use %s scanf("%d %d", &a, &b); scanf("%d,%d", &a, &b); 範例程式、執行結果

計算BMI (二) 輸入：身高(height), 體重(weight) 運算式： 輸出：你的BMI值為xx.xx BMI = weight / (height)2 BMI = weight / (height * height) 　（身高單位為公尺、體重單位為公斤。） 輸出：你的BMI值為xx.xx 執行結果