C

C Express

C Express

4 1 * * * * * * * .2 Q) (variable) ?A) Q) ?A) .

3 = .

int 4 .

(Q) ?100 0 (A) . .5 (variable): (constant): () 3.14, 100, A, Hello World!1212(Q) ?(A) . (literal) . . .6 (data type): ()() (100) (3.141592)(Q) ?(A) .

7 shortshort 2-3276832767int4-21474836482147483647longlong 4-21474836482147483647unsigned short short 2065535unsigned int 404294967295unsigned long long 404294967295char 1-128127unsigned char 10255float 41.2E-383.4E38double 82.2E-3081.8E3088

(identifier):

9 , _ _ C . (Q) ?sum_countking3n_pictures2nd_trydollor$doubleOOOOX// X// $X// 10 (keyword): C (reserved words) .auto double int struct breakelse long switch caseenum register typedef char extern return union constfloat short unsigned continuefor signed void defaultgoto sizeof volatile do if static while 11 : ; char c;int I;double interest_rate;int height, width;

12 char c;// c int i;// i double interest_rate;// interest_rate

c = 'a';// c 'a' i = 60;// i 60 interest_rate = 4.9;// interest_rate 82.9

13 = ;

char c = a;int i = 7;double interest_rate = 0.05;14 int main(void) { int count; int index; count = 0; index = 1; int sum; ...} .15 short, int, long

int CPU .16, 32, 64 (Q) ?(A) 16 int

short

long int 17 /* */ #include

int main(void) { short year = 0;// 0 . int sale = 0;// 0 . long total_sale = 0;// 0 .

year = 10;// 32 sale = 200000000;// 21 total_sale = year * sale;// 21 printf("total_sale = %d \n", total_sale);

printf("short : %d\n", sizeof(short)); printf("int : %d\n", sizeof(int)); printf("long : %d\n", sizeof(long));

return 0; } short : 2int : 4long : 418 signed, unsigned unsigned unsigned int

signed 19 #include int main(void) { int x; unsigned int y; x = 2147483647; printf("x = %d\n",x); printf("x+1 = %d\n",x+1); printf("x+2 = %d\n",x+2); printf("x+3 = %d\n",x+3);

y = 4294967295; printf("y = %u\n",y);// unsigned %u printf("y+1 = %u\n",y+1); printf("y+2 = %u\n",y+2); printf("y+3 = %u\n",y+3); } x = 2147483647 x+1 = -2147483648 x+2 = -2147483647 x+3 = -2147483646 y = 4294967295 y+1 = 0 y+2 = 1 y+3 = 2 !!20 (overflow):

21 .

22

.u Uunsigned int 123u 123Ul Llong123l 123Lul ULunsigned long123ul 123UL10

int x = 10; // 10 10 int 10. int y = 010; // 010 8 int 8. int z = 0x10; // 010 16 int 16.

23 /* */ #include

int main(void) { int x = 10; // 10 10 int 10. int y = 010; // 010 8 int 8. int z = 0x10; // 010 16 int 16.

printf("sizeof(10L) = %d\n", sizeof(10L)); printf("x = %d y = %d z = %d\n", x, y, z); printf("x = %d x = %#o x = %#x\n", x, x, x);

return 0; } sizeof(10L) = 4 x = 10 y = 8 z = 16 x = 10 x = 012 x = 0xa 24 (symbolic constant): () area = 3.141592 * radius * radius; area = PI * radius * radius;

income = salary - 0.15 * salary;income = salary - TAX_RATE * salary; . .25

26 #define /* */ #include #define PI 3.141592

int main(void) { float radius, area, circumference;//

printf(" :");// scanf("%f", &radius);//

area = PI * radius * radius;// circumference = 2.0 * PI * radius;//

printf(" %f.\n", radius);// printf(" %f %f.\n", area, circumference);

return 0; } 27 const /* */ #include

int main(void) { const double TAX_RATE = 0.15;// double income, salary;//

printf(" :");// scanf("%lf", &salary);// double %lf

income = salary - TAX_RATE * salary;// printf(" %lf.\n", income);//

return 0; } 28 .

0010100029 . . .

30 . , .() +3 + (-3)

31 (cont.) 0 0

32 2 . 2

33 2

34 /* 2 */ #include

int main(void) { int x = 3; int y = -3;

printf("x = %08X\n", x);// 8 16 . printf("y = %08X\n", y);// 8 16 . printf("x+y = %08X\n", x+y);// 8 16 .

return 0; } x = 00000003 y = FFFFFFFD x+y = 00000000 2 .35 . (ASCII: American Standard Code for Information Interchange) []8 () ! 33, A 65, B 66, a 97, b 98 !"#$%&'()*+,-./0123456789:;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~36 char char c;char answer;char code;char

code = 65;// A code = A; 37 /* */ #include

int main(void) { char code1 = 'A';// char code2 = 65;//

printf(" = %c\n", code1); printf(" = %c\n", code2); } = A = A (Q) 1 1 ?(A) 1 1 .38 () , , ,

char beep = 7; printf("%c", beep); char beep = \a; printf("%c", beep); 39 \00 (bell)\a7" (backspace)\b8 .(horizontal tab)\t9 .(newline)\n10 .(vertical tab)\v11 (form feed)\f12 . (carriage return)\r13 .\34 \39 (back slash)\\92 40 /* */ #include

int main(void) { printf(" \\ \n"); printf("'\\a' . \n"); printf("'\\007' . \n"); printf(" '\\007' \007 \n");

} \ '\a' . '\007' . '\007' 41

42 #1 32 16, 16 () 3.14

43 #2 ()

.10-38 10+38

44

45 /* */ #include

int main(void) { float x = 1.234567890123456789; double y = 1.234567890123456789;

printf("float =%d\n", sizeof(float)); printf("double =%d\n", sizeof(double)); printf("long double =%d\n", sizeof(long double));

printf("x = %30.25f\n",x); printf("y = %30.25f\n",y); return 0;} float =4 double =8 long double =8 x = 1.2345678806304932000000000 y = 1.2345678901234567000000000 46 3.141592(double) 3.141592F(float)

1.23456e4 = 12345.61.23456e-3 = 0.00123456

1.23456 2.// . .28// . 0e0 2e+10// + - . 9.26E3// 9.26e3// 47 #include

int main(void) { float x = 1e39; printf("x = %e\n",x); } C:\CPROGRAM\test\test.c(5) : warning C4056: overflow in floating-point constant arithmetic 48 #include

int main(void) { float x = 1.23456e-38; float y = 1.23456e-40; float z = 1.23456e-46;

printf("x = %e\n",x); printf("y = %e\n",y); printf("z = %e\n",z); } x = 1.234560e-038 y = 1.234558e-040 z = 0.000000e+000 49 !#include

int main(void) { double x;

x = (1.0e20 + 5.0)-1.0e20; printf("%f \n",x); return 0; } 0.000000 5.0 .50 Q & A

51