文章目錄
-
- 今日見聞
- 今日重要的三件事
- 記錄
-
- 科學上網：[Flutter: the good, the bad and the ugly – The ASOS Tech Blog – Medium](https://medium.com/asos-techblog/flutter-vs-react-native-for-ios-android-app-development-c41b4e038db9)
- CodeList 4-1 at P
- CodeList 4-2 at P
- CodeList 4-3 at P
- CodeList 4-4 at P
- CodeList 4-5 at P
- CodeList 4-6 at P
- CodeList 4-7 at P
- CodeList 4-8 at P
- CodeList 4-9 at P
- CodeList 4-10 at P
- CodeList 4-11 at P
- CodeList 4-12 at P
- CodeList 4-13 at P76
- CodeList 4-14 at P
- CodeList 4-15 at P78
- CodeList 4-16 at P
- CodeList 4-17 at P
今日見聞
入門教程和文檔 | Visual Studio - Visual Studio
今日重要的三件事
- 完成CPP第四章CodeList
- 工作需求要完成
- 實戰xcode開發App第三章
記錄
科學上網：Flutter: the good, the bad and the ugly – The ASOS Tech Blog – Medium
CodeList 4-1 at P
/* talkback.c -- 一個能為您提供一些資訊的對話程式 */
#include <stdio.h>
#include <string.h> // strlen()函數原型在這裡
#define DENSITY 62.4 //人體密度(機關: 磅/立方英尺)
int main(void)
{
float weight, volume;
int size, letters;
char name[40]; // name是一個有40個字元的數組.
printf("Hi! What`s your first name?\n");
scanf("%s", name);
printf("%s, what`s your weight in pounds?\n", name);
scanf("%f", &weight);
size = sizeof name;
letters = strlen(name);
volume = weight / DENSITY;
printf("Well! %s, your volume is %2.2f cubic feet.\n", name, volume);
printf("Also, your first name has %d letters ", letters);
printf("and we have %d bytes to stores it.\n", size);
return 0;
}
Panda-MBP:CodeList4-1 panda8z$ gcc -o talkback.out talkback.c
Panda-MBP:CodeList4-1 panda8z$ ./talkback.out
Hi! What`s your first name?
panda
panda, what`s your weight in pounds?
40
Well! panda, your volume is 0.64 cubic feet.
Also, your first name has 5 letters and we have 40 bytes to stores it.
Panda-MBP:CodeList4-1 panda8z$
CodeList 4-2 at P
/* praise1.c -- 使用不同類别的字元串 */
#include <stdio.h>
#define PRAISE "What a super marvelous name!"
int main(void)
{
char name[40];
printf("What`s your name?\n");
scanf("%s", name);
printf("Hello %s, %s\n", name, PRAISE);
return 0;
}
Panda-MBP:CodeList4-2 panda8z$ gcc -o praise1.out praise1.c
Panda-MBP:CodeList4-2 panda8z$ ./praise1.out
What`s your name?
panda
Hello panda, What a super marvelous name!
Panda-MBP:CodeList4-2 panda8z$
CodeList 4-3 at P
/* praise2.c */
#include <stdio.h>
#include <string.h> // strlen() is here
#define PRAISE "What a super marvelous name!"
int main(void)
{
char name[40];
printf("What`s your name?\n");
scanf("%s", name);
printf("Hello, %s. %s\n", name, PRAISE);
printf("Your name of %d letters occupies %d memory cells.\n",strlen(name), sizeof name);
printf("The phrase of prasie has %d letters",strlen(PRAISE));
printf("and occupies %d memory cells.\n", sizeof(PRAISE));
}
Panda-MBP:CodeList4-3 panda8z$ gcc -o praise2.out praise2.c
praise2.c:12:66: warning: format specifies type 'int' but the
Panda-MBP:CodeList4-3 panda8z$ gcc -o praise2.out praise2.c
praise2.c:12:66: warning: format specifies type 'int' but the
argument has type 'unsigned long' [-Wformat]
...%d letters occupies %d memory cells.\n",strlen(name)...
~~ ^~~~~~~~~~~~
%lu
praise2.c:12:80: warning: format specifies type 'int' but the
argument has type 'unsigned long' [-Wformat]
...%d memory cells.\n",strlen(name), sizeof name);
~~ ^~~~~~~~~~~
%lu
praise2.c:13:50: warning: format specifies type 'int' but the
argument has type 'unsigned long' [-Wformat]
...phrase of prasie has %d letters",strlen(PRAISE));
~~ ^~~~~~~~~~~~~~
%lu
praise2.c:14:47: warning: format specifies type 'int' but the
argument has type 'unsigned long' [-Wformat]
...occupies %d memory cells.\n", sizeof(PRAISE));
~~ ^~~~~~~~~~~~~~
%lu
4 warnings generated.
Panda-MBP:CodeList4-3 panda8z$ ./praise2.out
What`s your name?
panda panda
Hello, panda. What a super marvelous name!
Your name of 5 letters occupies 40 memory cells.
The phrase of prasie has 28 lettersand occupies 29 memory cells.
Panda-MBP:CodeList4-3 panda8z$
CodeList 4-4 at P
/* pizza.c -- 在這個匹薩餅的例子中使用定義常量 */
#include <stdio.h>
#define PI 3.14159
int main(void)
{
float area, circum, radius;
printf("What is the radius of your pizza?\n");
scanf("%f", &radius);
area = PI * radius * radius;
circum = 2.0 * PI * radius;
printf("Your basic pizza parameters are as follows: \n");
printf("circumference = %1.2f, area = %1.2f\n", circum, area);
return 0;
}
這個編譯說錯誤是因為我的printf語句不正常，确實寫錯了
Panda-MBP:CodeList4-4 panda8z$ gcc -o pizza.out pizza.c
pizza.c:13:5: warning: implicit declaration of function
'printd' is invalid in C99
[-Wimplicit-function-declaration]
printd("circumference = %1.2f, area = %1.2f\n", c...
^
1 warning generated.
Undefined symbols for architecture x86_64:
"_printd", referenced from:
_main in pizza-e528df.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v
to see invocation)
正确的輸出
Panda-MBP:CodeList4-4 panda8z$ gcc -o pizza.out pizza.c
Panda-MBP:CodeList4-4 panda8z$ ./pizza.out
What is the radius of your pizza?
12
Your basic pizza parameters are as follows:
circumference = 75.40, area = 452.39
Panda-MBP:CodeList4-4 panda8z$
CodeList 4-5 at P
/* defines.c -- 使用limit.h和floath中定義的常量 */
#include <stdio.h>
#include <limits.h> //整數限制
#include <float.h> //浮點數限制
int main(void)
{
printf("Some number limits for this system: \n");
printf("Biggest int: %d\n", INT_MAX);
printf("Smallest unsigned long: %lld\n", LLONG_MIN);
printf("One byte = %d bits on this system.\n", CHAR_BIT);
printf("Largest double: %e.\n", DBL_MAX);
printf("Smallest normal float: %e\n", FLT_MIN);
printf("float pricision = %d digits\n", FLT_DIG);
printf("float epsilon = %e\n", FLT_EPSILON);
return 0;
}
Panda-MBP:CodeList4-5 panda8z$ gcc -o defines.out defines.c
Panda-MBP:CodeList4-5 panda8z$ ./defines.out
Some number limits for this system:
Biggest int: 2147483647
Smallest unsigned long: -9223372036854775808
One byte = 8 bits on this system.
Largest double: 1.797693e+308.
Smallest normal float: 1.175494e-38
float pricision = 6 digits
float epsilon = 1.192093e-07
Panda-MBP:CodeList4-5 panda8z$
CodeList 4-6 at P
/* printout.c -- 使用轉換說明符 */
#include <stdio.h>
#define PI 3.141593
int main(void)
{
int number = 5;
float expresso = 13.5;
int cost = 3100;
printf("The %d CEOs drank %f cups of expresso.\n", number, expresso);
printf("The value of pi is %f.\n", PI);
printf("FarewellA thou art too dear for my prossessing, \n");
printf("%c%d\n",'$', 2 * cost);
return 0;
}
Panda-MBP:CodeList4-6 panda8z$ gcc -o printout.out printout.c
Panda-MBP:CodeList4-6 panda8z$ ./printout.out
The 5 CEOs drank 13.500000 cups of expresso.
The value of pi is 3.141593.
FarewellA thou art too dear for my prossessing,
$6200
Panda-MBP:CodeList4-6 panda8z$
CodeList 4-7 at P
/* width.c -- 字段寬度 */
#include <stdio.h>
#define PAGES 931
int main(void)
{
printf("*%d*\n",PAGES);
printf("*%2d*\n",PAGES);
printf("*%10d*\n",PAGES);
printf("*%-10d*\n",PAGES);
return 0;
}
Panda-MBP:CodeList4-7 panda8z$ gcc -o width.out width.c
Panda-MBP:CodeList4-7 panda8z$ ./width.out
*931*
*931*
* 931*
*931 *
Panda-MBP:CodeList4-7 panda8z$
CodeList 4-8 at P
/* float.c -- 一些浮點數的組合 */
#include <stdio.h>
int main(void)
{
const double RENT = 3852.99; //以const方法定義常量
printf("*%f*\n",RENT);
printf("*%e*\n",RENT);
printf("*%4.2f*\n",RENT);
printf("*%3.1f*\n",RENT);
printf("*%10.3ff*\n",RENT);
printf("*%10.3e*\n",RENT);
printf("*%+4.2f*\n",RENT);
printf("*%010.2f*\n",RENT);
return 0;
}
Panda-MBP:CodeList4-8 panda8z$ gcc -o float.out float.c
Panda-MBP:CodeList4-8 panda8z$ ./float.out
*3852.990000*
*3.852990e+03*
*3852.99*
*3853.0*
* 3852.990f*
* 3.853e+03*
*+3852.99*
*0003852.99*
Panda-MBP:CodeList4-8 panda8z$
CodeList 4-9 at P
/* flags.c -- 一些标志的使用示例 */
#include <stdio.h>
int main(void)
{
printf("%x, %X, %#x\n", 31, 31, 31);
printf("**%d**% d**% d**\n", 42, 42, -42);
printf("**%5d**%5.3d**%05d**%05.3d**\n", 6, 6, 6, 6);
return 0;
}
Panda-MBP:CodeList4-9 panda8z$ gcc -o flags.out flags.c
Panda-MBP:CodeList4-9 panda8z$ ./flags.out
1f, 1F, 0x1f
**42** 42**-42**
** 6** 006**00006** 006**
Panda-MBP:CodeList4-9 panda8z$
CodeList 4-10 at P
/* string.c -- 字元串格式化 */
#include <stdio.h>
#define BLURB "Authentic imitation!"
int main(void)
{
printf("/%2s/\n", BLURB);
printf("/%24s/\n", BLURB);
printf("/%24.5s/\n", BLURB);
printf("/%-24.5s/\n", BLURB);
return 0;
}
Panda-MBP:CodeList4-10 panda8z$ gcc -o string.out string.c
Panda-MBP:CodeList4-10 panda8z$ ./string.out
/Authentic imitation!/
/ Authentic imitation!/
/ Authe/
/Authe /
Panda-MBP:CodeList4-10 panda8z$
CodeList 4-11 at P
/* intconv.c -- 一些不比對的整數轉換 */
#include <stdio.h>
#define PAGES 336
#define WORDS 65618
int main(void)
{
short num = PAGES;
short mnum = -PAGES;
printf("num as short and unsigned short: %hd %hu\n", num, num);
printf("-num as short and unsinged short: %hd %hu\n", mnum, mnum);
printf("num as int and char: %d %c\n", num, num);
printf("WORDS as int, short, and char: %d %hd %c\n", WORDS, WORDS, WORDS);
return 0;
}
Panda-MBP:CodeList4-11 panda8z$ gcc -o intconv.out intconv.c
intconv.c:13:65: warning: format specifies type 'short' but the argument has type 'int' [-Wformat]
printf("WORDS as int, short, and char: %d %hd %c\n", WORDS, WORDS, WORDS);
~~~ ^~~~~
%d
intconv.c:4:15: note: expanded from macro 'WORDS'
#define WORDS 65618
^~~~~
1 warning generated.
Panda-MBP:CodeList4-11 panda8z$ ./intconv.out
num as short and unsigned short: 336 336
-num as short and unsinged short: -336 65200
num as int and char: 336 P
WORDS as int, short, and char: 65618 82 R
Panda-MBP:CodeList4-11 panda8z$
CodeList 4-12 at P
/* floatcnv.c -- 不比對的浮點數轉換 */
#include <stdio.h>
int main (void)
{
float n1 = 3.0;
double n2 = 3.0;
long n3 = 2000000000;
long n4 = 1234567890;
printf("%.1e %.1e %.1e %.1e\n", n1, n2, n3, n4);
printf("%1d %1d\n", n3, n4);
printf("%1d %1d %1d %1d\n", n1, n2, n3, n4);
return 0;
}
Panda-MBP:CodeList4-12 panda8z$ gcc -o floatcnv.out floatcnv.c
floatcnv.c:10:45: warning: format specifies type 'double' but the argument has type 'long' [-Wformat]
printf("%.1e %.1e %.1e %.1e\n", n1, n2, n3, n4);
~~~~ ^~
%.1ld
floatcnv.c:10:49: warning: format specifies type 'double' but the argument has type 'long' [-Wformat]
printf("%.1e %.1e %.1e %.1e\n", n1, n2, n3, n4);
~~~~ ^~
%.1ld
floatcnv.c:11:25: warning: format specifies type 'int' but the argument has type 'long' [-Wformat]
printf("%1d %1d\n", n3, n4);
~~~ ^~
%1ld
floatcnv.c:11:29: warning: format specifies type 'int' but the argument has type 'long' [-Wformat]
printf("%1d %1d\n", n3, n4);
~~~ ^~
%1ld
floatcnv.c:12:33: warning: format specifies type 'int' but the argument has type 'float' [-Wformat]
printf("%1d %1d %1d %1d\n", n1, n2, n3, n4);
~~~ ^~
%1f
floatcnv.c:12:37: warning: format specifies type 'int' but the argument has type 'double' [-Wformat]
printf("%1d %1d %1d %1d\n", n1, n2, n3, n4);
~~~ ^~
%1f
floatcnv.c:12:41: warning: format specifies type 'int' but the argument has type 'long' [-Wformat]
printf("%1d %1d %1d %1d\n", n1, n2, n3, n4);
~~~ ^~
%1ld
floatcnv.c:12:45: warning: format specifies type 'int' but the argument has type 'long' [-Wformat]
printf("%1d %1d %1d %1d\n", n1, n2, n3, n4);
~~~ ^~
%1ld
8 warnings generated.
Panda-MBP:CodeList4-12 panda8z$ ./floatcnv.out
3.0e+00 3.0e+00 0.0e+00 0.0e+00
2000000000 1234567890
2000000000 1234567890 -795279276 77992
Panda-MBP:CodeList4-12 panda8z$
CodeList 4-13 at P76
/* prntval.c -- 發現printf()函數的傳回值 */
#include <stdio.h>
int main (void)
{
int bph2o = 212;
int rv;
rv = printf("%d F is water`s boiling point.\n", bph2o);
printf("The printf() function printed %d characters.\n", rv);
return 0;
}
Panda-MBP:CodeList4-13 panda8z$ gcc -o prntval.out prntval.c
Panda-MBP:CodeList4-13 panda8z$ ./prntval.out
212 F is water`s boiling point.
The printf() function printed 32 characters.
Panda-MBP:CodeList4-13 panda8z$
CodeList 4-14 at P
/* longstrg.c -- 列印較長的字元串 */
#include <stdio.h>
int main (void)
{
printf("Here is one way to print a ");
printf("long string.\n");
printf("Here is another way to print a \
long string.\n");
printf("Here`s the newest way to print a"
"long string.\n");
return 0;
}
Panda-MBP:CodeList4-14 panda8z$ gcc -o longstrg.out longstrg.c
Panda-MBP:CodeList4-14 panda8z$ ./longstrg.out
Here is one way to print a long string.
Here is another way to print a long string.
Here`s the newest way to print along string.
Panda-MBP:CodeList4-14 panda8z$
CodeList 4-15 at P78
/* input.c -- 什麼情況下使用& */
#include <stdio.h>
int main(void)
{
int age;
float assets;
char pet[30];
printf("Enter your age, assets, and favorite pet.\n");
scanf("%d %f", &age, &assets);
scanf("%s",pet);
printf("%d $%.2f %s\n", age, assets, pet);
return 0;
}
Panda-MBP:CodeList4-15 panda8z$ gcc -o input.out input.c
Panda-MBP:CodeList4-15 panda8z$ ./input.out
Enter your age, assets, and favorite pet.
27 cat
27 $0.00 cat
Panda-MBP:CodeList4-15 panda8z$ ./input.out
Enter your age, assets, and favorite pet.
27
hoby
27 $0.00 hoby
Panda-MBP:CodeList4-15 panda8z$ ./input.out
Enter your age, assets, and favorite pet.
27
234234
cat
27 $234234.00 cat
Panda-MBP:CodeList4-15 panda8z$ ./input.out
Enter your age, assets, and favorite pet.
sdf
0 $0.00 sdf
Panda-MBP:CodeList4-15 panda8z$
CodeList 4-16 at P
/* varwid.c -- 使用可變寬度的輸出字段 */
#include <stdio.h>
int main(void)
{
unsigned width, precision;
int number = 256;
double weight = 242.5;
printf("What field width?\n");
scanf("%d", &width);
printf("The number is: %*d: \n",width, number);
printf("Now enter a width and a precision:\n");
scanf("%d %d", &width, &precision);
printf("Weight = %*.*f\n", width, precision, weight);
return 0;
}
Panda-MBP:CodeList4-16 panda8z$ gcc -o varwid.out varwid.c
Panda-MBP:CodeList4-16 panda8z$ ./varwid.out
What field width?
2
The number is: 256:
Now enter a width and a precision:
33
44
Weight = 242.50000000000000000000000000000000000000000000
Panda-MBP:CodeList4-16 panda8z$
CodeList 4-17 at P
/* skip2.c -- 跳過輸入的頭兩個整數 */
#include <stdio.h>
int main(void)
{
int n;
printf("Please enter three integers: \n");
scanf("%*d %*d %d", &n);
printf("The last integer was %d\n", n);
return 0;
}
Panda-MBP:CodeList4-17 panda8z$ gcc -o skip2.out skip2.c
skip2.c:8:16: warning: more '%' conversions than data arguments [-Wformat]
scanf("%d %d %d", &n);
~^
1 warning generated.
Panda-MBP:CodeList4-17 panda8z$ ./skip2.out
Please enter three integers:
5 6 8
Segmentation fault: 11
Panda-MBP:CodeList4-17 panda8z$ gcc -o skip2.out skip2.c
skip2.c:8:20: warning: more '%' conversions than data arguments [-Wformat]
scanf("%d %*d %d", &n);
~^
1 warning generated.
Panda-MBP:CodeList4-17 panda8z$ gcc -o skip2.out skip2.c
Panda-MBP:CodeList4-17 panda8z$ ./skip2.out
Please enter three integers:
3 4 5
The last integer was 5
Panda-MBP:CodeList4-17 panda8z$