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函数大全(q,r开头)

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发表于 2004-10-4 02:55 |只看该作者 |倒序浏览

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<

>函数名: qsort 
功能: 使用快速排序例程进行排序
用法: void qsort(void *base, int nelem, int width, int (*fcmp)());
程序例: 
<

>#include <STDIO.H>
#include <STDLIB.H>
#include <STRING.H>
<

>int sort_function( const void *a, const void *b); 
<

>char list[5][4] = { "cat", "car", "cab", "cap", "can" };

<

>int main(void)
{
int x; 
<

>qsort((void *)list, 5, sizeof(list[0]), sort_function);
for (x = 0; x < 5; x++)
printf("%s\n", list[x]);
return 0;
} 
<

>int sort_function( const void *a, const void *b)
{
return( strcmp(a,b) );
} 



<

>函数名: qsort 
功能: 使用快速排序例程进行排序
用法: void qsort(void *base, int nelem, int width, int (*fcmp)());
程序例: 
<

>#include <STDIO.H>
#include <STDLIB.H>
#include <STRING.H>
<

>int sort_function( const void *a, const void *b); 
<

>char list[5][4] = { "cat", "car", "cab", "cap", "can" };

<

>int main(void)
{
int x; 
<

>qsort((void *)list, 5, sizeof(list[0]), sort_function);
for (x = 0; x < 5; x++)
printf("%s\n", list[x]);
return 0;
} 
<

>int sort_function( const void *a, const void *b)
{
return( strcmp(a,b) );
}
<

>


<

>函数名: raise 
功能: 向正在执行的程序发送一个信号
用法: int raise(int sig);
程序例: 
<

>#include <SIGNAL.H>
<

>int main(void)
{
int a, b; 
<

>a = 10;
b = 0;
if (b == 0)
/* preempt divide by zero error */
raise(SIGFPE);
a = a / b;
return 0;
}


<

>函数名: rand 
功能: 随机数发生器
用法: void rand(void);
程序例: 
<

>#include <STDLIB.H>
#include <STDIO.H>
<

>int main(void)
{
int i; 
<

>printf("Ten random numbers from 0 to 99\n\n");
for(i=0; i<10; i++)
printf("%d\n", rand() % 100);
return 0;
}


<

>函数名: randbrd 
功能: 随机块读
用法: int randbrd(struct fcb *fcbptr, int reccnt);
程序例: 
<

>#include <

ROCESS.H>
#include <STRING.H>
#include <STDIO.H>
#include <DOS.H>
<

>int main(void)
{
char far *save_dta;
char line[80], buffer[256];
struct fcb blk;
int i, result; 
<

>/* get user input file name for dta */
printf("Enter drive and file name (no path - i.e. a:file.dat)\n");
gets(line); 
<

>/* put file name in fcb */
if (!parsfnm(line, &blk, 1))
{
printf("Error in call to parsfnm\n");
exit(1);
}
printf("Drive #%d File: %s\n\n", blk.fcb_drive, blk.fcb_name); 
<

>/* open file with DOS FCB open file */
bdosptr(0x0F, &blk, 0); 
/* save old dta, and set new one */
save_dta = getdta();
setdta(buffer); 
/* set up info for the new dta */
blk.fcb_recsize = 128;
blk.fcb_random = 0L;
result = randbrd(&blk, 1); 
/* check results from randbrd */
if (!result)
printf("Read OK\n\n");
else
{
perror("Error during read");
exit(1);
} 
/* read in data from the new dta */
printf("The first 128 characters are:\n");
for (i=0; i<128; i++)
putchar(buffer); $ R7 t& J1 Q# O r- Z
/* restore previous dta */
& d l. {' E$ D+ s+ Usetdta(save_dta); 4 o4 _' E0 q! `/ }- Y
return 0; * M, T0 z5 [2 A, V5 T1 O
} # Q/ `4 W2 [. ]7 `3 w

$ o3 @0 p( _2 O7 Q; C& T函数名: randbwr 
, G8 `9 H5 G- w P" v( f功能: 随机块写
) m4 s$ @2 m$ B6 d7 q% I0 X8 |用法: int randbwr(struct fcp *fcbptr, int reccnt);
" w4 }( c' h q程序例: 
; D: O& g$ H) L#include <PROCESS.H>% v0 ~, X/ X+ m7 ^% t7 N2 z
#include <STRING.H> N+ D8 f& f' d; K( a0 }! q1 B
#include <STDIO.H>$ C" H% N2 f. A
#include <DOS.H>
1 g. S. O$ r1 k U$ [, j1 `* x$ w. gint main(void)
( k+ H! L- C# j& i7 E9 D! W{ . T( X, C- K" g5 S8 A
char far *save_dta;
* R' h' X/ Z- F# \2 ?9 i wchar line[80];
) Q4 w8 S0 @4 M0 ]4 l( _char buffer[256] = "RANDBWR test!"; : Q- |; Q5 `- u3 J
struct fcb blk; $ t( F" l; z. ^( e
int result; 
8 n' o/ q$ X; T! g) |& k3 {/* get new file name from user */ 9 R- U b9 Y( E( r" e* J
printf("Enter a file name to create (no path - ie. a:file.dat\n");
( W1 A l/ Q8 h9 g; Z0 `gets(line); , ?$ p- E( m9 h5 M$ o) _2 b1 C. f; L
/* parse the new file name to the dta */
# h( i- {& o) X* t8 H, aparsfnm(line,&blk,1);
5 K, @7 T5 K- t0 O- `printf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
) Z& f% z" y; f6 d/* request DOS services to create file */
% n5 L3 w$ j2 A- z) H( _5 Eif (bdosptr(0x16, &blk, 0) == -1)
+ d4 l: H* j0 u5 H. w6 f- D, D8 j{ 8 k2 K% U8 $ B6 G! M
perror("Error creating file");
, s! A+ U) w0 G. O% l1 kexit(1);
/ F" J2 T" E- p( $ e} / W5 r; K4 A$ ?. |# H7 q& j H
/* save old dta and set new dta */ 4 ]3 x- l9 Z, V' U
save_dta = getdta();
: }8 A. L* I% z) Z% Psetdta(buffer); 8 s8 ^2 p7 B2 i. `- I( N- u/ Y
/* write new records */ 8 J' D, [6 V: u0 I8 X- M
blk.fcb_recsize = 256; ; H% {6 J; D% a2 P( a- d5 f6 j+ ^
blk.fcb_random = 0L;
0 _$ B/ l+ [4 W1 X+ qresult = randbwr(&blk, 1); 
 h* x2 i: O$ x- cif (!result) - k6 u# s% Q" z8 O. S* J
printf("Write OK\n");
- Y6 c. v5 p; @/ e" [else
& G! d, ?) y: S* C; @{ ! T8 M1 y8 t* ?" k. U! Y8 e3 R: S) a( k
perror("Disk error");
, ? w5 l2 y4 `! d3 x3 Fexit(1); # Y8 e& g" l1 r- ~
} + Q6 A+ Y3 I: f, I; j* {& `
/* request DOS services to close the file */ 0 P$ M* I+ C5 T: o& y( Y
if (bdosptr(0x10, &blk, 0) == -1)
# g. d8 `1 R# _{
 d) ^9 F; E* T* ]4 x6 Sperror("Error closing file"); - e( w" Y8 N: T. T% r3 r
exit(1); + C2 P6 Y1 I( _ }, E) w- |0 j X$ N
} 
' {2 X- b- ~3 y: }/* reset the old dta */ 3 i, a% u; g. y* J( ?% Y8 C8 F* G& W# p3 ?
setdta(save_dta); 
' f+ l. Y# c. o" q9 @return 0; 1 t& F" E+ }6 f/ J$ L' _
} + d. o2 h( Y& I9 e2 c2 X& f

9 ?% i7 ?+ H$ z: y. h8 f3 `( D( a O
函数名: random 
! X! M' B1 o; `3 g. E6 i% M. {功能: 随机数发生器 3 O4 r8 h, f; j' b! K
用法: int random(int num);
: m: ]- S3 c) r程序例: 
" r* F4 O/ [- o" D$ p5 @# ?) s4 ^#include <STDLIB.H>
) }8 z( _2 ~. ^9 S. m9 ^#include <STDIO.H>5 L/ T/ Z8 p* t i% B& y M
#include <TIME.H>/ u, j3 H' q1 P# N
/* prints a random number in the range 0 to 99 */ 5 m4 G' D; F u3 O. a1 H! o9 Y
int main(void)
8 y0 u1 N% K& O0 _* ?- X4 W: q d/ S{
. M$ H" Q8 s2 b" [2 M$ Erandomize(); , c" X8 n# e6 ]
printf("Random number in the 0-99 range: %d\n", random (100)); ( A1 ]0 h+ t) B' W2 S
return 0; * \( P b$ R* ]! U, c
}
, |$ O* p; d, q. S( a/ ^6 A& N0 N5 D) }; R8 }1 `

$ C: h+ b9 l6 s1 T7 w函数名: randomize / P# P4 ^% o! s4 _6 D7 f# Z
功能: 初始化随机数发生器 $ D( n% c/ r: Z3 ?, H3 R+ b0 t7 z
用法: void randomize(void); , P: z+ F1 a6 O( U; q9 y
程序例: $ c/ O$ z) [+ o) x! b) r
#include <STDLIB.H>
$ x/ j. D0 V' ?5 M% _#include <STDIO.H>
8 r; y3 Y( H9 `+ |#include <TIME.H>
0 c. I, m4 m7 K& ^6 lint main(void)
1 U8 G. @8 Z7 M" d: A0 x+ Z{ 4 o- Y* {9 I \- X
int i; 0 }% f# J _: U$ G/ Z0 q0 ~- \# M& U% y
randomize(); - |4 C( |; F- E \ p @1 d
printf("Ten random numbers from 0 to 99\n\n");
0 Y& H6 i1 f: X2 Pfor(i=0; i<10; i++)
5 t8 Z0 ]8 Y+ N0 Xprintf("%d\n", rand() % 100);
/ `% d# P H7 O5 a9 ?" Nreturn 0;
4 E6 S Z3 k1 }}
8 A6 n2 F2 A* E/ H$ V# L' L
: f4 s7 B* l# a. H, @5 H* p( ?+ }' ^6 [5 j: F4 q% f; i8 _
函数名: read 
1 e. |* W1 }/ r1 @' t; @. u) ]功能: 从文件中读
. n7 f" i# x( M用法: int read(int handle, void *buf, int nbyte); # G4 W3 D( j! N9 r% a/ M* q9 U! i
程序例: 
, `4 t, S z( U( c# h5 D* I9 M#include <STDIO.H>* T0 o7 A3 M% f# C
#include <IO.H>
( W1 |# ~4 |: H0 ]5 s$ x$ o) V6 I5 m#include <ALLOC.H>+ B) e: o) i1 Z: g5 ~* h
#include <FCNTL.H>
% ?% D) z6 L l$ ~6 z5 {/ @#include <PROCESS.H>2 h" i( f+ l# f& Y4 `
#include <SYS\STAT.H>6 H( C9 y8 ^0 d5 k* S' g: }9 n8 b
int main(void) 1 `2 u7 p- j0 R- V1 S4 K/ E
{ " f" P9 G2 {6 n7 t( W
void *buf;
$ I; q2 {! w9 K7 P3 ~8 ~int handle, bytes; 0 h y6 Q. u; Z0 B7 B( k
buf = malloc(10); 
" U# i6 x2 H& @5 \/* # E2 T) f" O! U) i3 ~
Looks for a file in the current directory named TEST.$$$ and attempts 5 j- Z3 w0 I, \) W9 z4 y
to read 10 bytes from it. To use this example you should create the
) H& q. m! U5 ofile TEST.$$$ ( j0 t! @' E# ^. r
*/ 5 N- B5 V7 D) \, G2 c
if ((handle =
4 h6 H/ S, X! u$ W/ d L; popen("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1)
9 @5 G8 K- @ {2 C1 J4 G{ ! @3 Z' }" O- z
printf("Error Opening File\n"); 5 Q5 s" B" T! B2 j1 n6 l3 X
exit(1); 6 |; p, B- f4 f- D( C! F4 s8 y
} 
: o$ E! t% a6 V) I8 @if ((bytes = read(handle, buf, 10)) == -1) {
0 t: u0 h/ q: I7 Nprintf("Read Failed.\n");
 d5 {( r( P, nexit(1);
* G c0 B- C2 T- Q1 S$ L} * F6 x( w5 ?. D1 M" J
else { ' C" E; K8 F. ]2 t% `( Y
printf("Read: %d bytes read.\n", bytes); 1 J0 L2 G/ ~ R6 c7 [
}
9 t) I s% g+ o: _- e: X greturn 0; 3 C0 t' i: }0 f" s
} * X& o6 r$ N3 |" V( B# S
8 k# v6 t) [3 U& e# J4 A8 L

: D+ I0 \* V, a+ m" j1 ^) I函数名: realloc 
1 c/ y7 f6 e" ~# s. O功能: 重新分配主存 6 Y- x# ?1 S5 |3 X8 l
用法: void *realloc(void *ptr, unsigned newsize); 2 u3 \- H9 u' d) Z" z$ o* B9 @
程序例: 
* a7 z! b3 b# o- Y/ t7 R#include <STDIO.H>8 t# e. ~# Z/ S3 m! n# x: `
#include <ALLOC.H>
, I7 i5 ]0 I1 i#include <STRING.H>
 i$ n8 `/ W1 E, k: n& Uint main(void) 9 t$ J+ |) l) y- I) K
{
; |0 H: Y4 W4 i+ Y& j9 O" S7 x) y8 _char *str; 
* E7 R) i5 y, Z) t1 S8 a/* allocate memory for string */
, z* H5 A1 H3 l6 m: E# s' jstr = malloc(10); 
8 Q6 e. X5 v/ b: {% y# A/ r/ \/* copy "Hello" into string */ 7 A" h2 b. v( R( W
strcpy(str, "Hello"); 3 H* P8 O+ X! V/ b/ |
printf("String is %s\n Address is %p\n", str, str);
9 {" H5 f( p- a; d5 W' @str = realloc(str, 20); ( E4 p2 x4 B& L& r% P- P- f8 w
printf("String is %s\n New address is %p\n", str, str); 
2 W' I' H* z( q: q/* free memory */
 [. v( p, X- d( y. rfree(str); ' P& U# c8 U3 x7 m- c" _2 ^
return 0;
" v/ @5 m7 U2 j0 h/ h6 N}
- g9 H8 O( t$ t4 V9 o: L* ~
8 p7 r! p$ \( ~1 D( p+ r; _. D% y& X7 q& \8 |
函数名: rectangle 
9 T: N+ I2 H* D/ K9 i功能: 画一个矩形 6 T1 z+ J* v9 E: ^8 e3 Y; L! \
用法: void far rectangle(int left, int top, int right, int bottom); 4 Y' D# O; {" n# L. _, Z
程序例: 
; @7 O, g9 r) o ]! D- `3 D8 T#include <GRAPHICS.H>3 f% f) i: G6 u1 U( {/ m
#include <STDLIB.H>
 x5 {$ d$ ]3 V9 {% X C#include <STDIO.H>3 j7 ^2 j6 z9 u5 L+ h
#include <CONIO.H>) b3 P- K3 p8 {
int main(void)
; S' [ B3 W* D. x0 k) E) Y{
- W1 [/ m: d( ]! q/* request auto detection */ ! D: A" x! k3 d
int gdriver = DETECT, gmode, errorcode;
+ N5 c7 I4 T. e" Oint left, top, right, bottom; ' E7 y7 Q5 p2 A9 x2 ~6 k
/* initialize graphics and local variables */ : ~6 K- ]) w: G# T
initgraph(&gdriver, &gmode, ""); 
" F3 c- F, Z5 e9 f' b; ?/* read result of initialization */ 7 v' k& G& }7 v/ D* s
errorcode = graphresult();
4 ~2 ]( e1 O2 E( Z. ?- Hif (errorcode != grOk) /* an error occurred */
& A! l0 w! m7 {% s0 w+ W5 _{ ! O2 p1 L F6 M! D, \" Z5 f
printf("Graphics error: %s\n", grapherrormsg(errorcode));
! \1 F% C6 z* B9 jprintf("Press any key to halt:"); ) {3 B' [6 D/ \4 L+ k, J
getch(); , l* ]: G$ P% Z
exit(1); /* terminate with an error code */ - p7 e/ \( I8 K2 a- {8 c
} 
1 V" ~5 P, }6 |* Y2 Q; [$ S9 {left = getmaxx() / 2 - 50; & T& ~, Q3 o, i% W/ b0 \9 T
top = getmaxy() / 2 - 50;
$ ?; D3 n% n8 \! y6 Y d% x2 ?right = getmaxx() / 2 + 50; $ w' d: N! C1 S' x- h
bottom = getmaxy() / 2 + 50; - Y7 }8 B6 \/ |
/* draw a rectangle */ % N, w6 j* f/ J7 P
rectangle(left,top,right,bottom); 
# I- l$ {) C- B* R7 M9 y/* clean up */ : @8 A) } S* G3 G
getch(); # N8 r/ l# h! ~" C" D
closegraph();
3 o4 C d! Q/ H& K+ r1 J, freturn 0; 8 o: k2 C: x/ j# U* Z( Y% k
}
. d0 P+ `& I6 z9 t
5 c+ v! T% [/ K( d" s& R7 J$ z6 S. ]: E" m9 `0 E0 P* C
函数名: registerbgidriver 
& P4 h3 q7 B- k& b" J功能: 登录已连接进来的图形驱动程序代码 : Z7 L, S3 s/ A- L
用法: int registerbgidriver(void(*driver)(void));
" O8 C! r) P: {程序例: 
! O$ a# Q& R- L( L#include <GRAPHICS.H>4 m G6 g' ~5 M. u: Y$ K% H# y
#include <STDLIB.H>
7 ^4 u" E f, u! Y! _#include <STDIO.H>
. t. N& k+ F& x, v#include <CONIO.H>
5 y' y* d2 r* z3 O: `int main(void)
% f. q9 V& w) \. L{
9 x3 V" Z9 L0 c- g7 h) @/ e- d/* request auto detection */
1 w' l4 ]/ W) m# ^int gdriver = DETECT, gmode, errorcode; ( S0 {5 a: k% U) j% R& L
/* register a driver that was added into graphics.lib */
+ H* K% G' z; | }. jerrorcode = registerbgidriver(EGAVGA_driver); ! W. f. m/ k# h1 d" N5 P
/* report any registration errors */
% A& z. {% `- `, sif (errorcode < 0)
7 }7 R! \+ F! t4 r3 q- J{
7 o! x* C! u: l! L' Eprintf("Graphics error: %s\n", grapherrormsg(errorcode)); l9 G3 g! T/ V X; I: n3 @3 P( `
printf("Press any key to halt:"); 7 A: a7 x3 i: u c t7 U8 q
getch(); # ^" T* s- i6 d4 `6 W; M
exit(1); /* terminate with an error code */
9 J7 \% M0 o1 J9 P" K- `. U} / I2 M, C$ h0 ^6 \/ d% Q
/* initialize graphics and local variables */
9 ~. q9 Z ~7 binitgraph(&gdriver, &gmode, ""); 
1 y2 B5 W* X' H1 n0 O- _- F9 l+ W/* read result of initialization */
& ?. N3 @. d* W- \/ R/ ^4 berrorcode = graphresult();
$ R7 I0 b* M/ i3 k+ @3 bif (errorcode != grOk) /* an error occurred */ 8 B9 g$ e2 u5 t# N' H' Q
{ / J6 V4 j9 H, }% E8 _
printf("Graphics error: %s\n", grapherrormsg(errorcode));
3 q9 q4 @7 j2 i! l& k/ Nprintf("Press any key to halt:");
& Z7 ?7 x9 w t N: Ugetch(); * j* r7 y* c" n7 r7 S v
exit(1); /* terminate with an error code */ / o- F$ }8 o1 \ P
} , @; `$ _) s8 J X
/* draw a line */
1 w% A& p4 |. A0 d' |4 Kline(0, 0, getmaxx(), getmaxy()); ( B+ c# l( \: p: K! N
/* clean up */
9 z. M. C2 L* D# N* ]9 O! ggetch(); 2 q7 h6 [# f+ E/ d+ g
closegraph();
! X4 c' G$ j6 |return 0; 3 u# v4 |% e% E+ Z, G2 L j
}
' ^2 }. {3 h! T1 y) N3 \; `
( }! n. J: t8 H. C7 o) S
7 K( {( ]5 o2 F, e* K( f函数名: remove 
7 i1 R( h( p$ N! K5 G' `功能: 删除一个文件 # G ?5 V+ j2 ~+ \
用法: int remove(char *filename); : c6 e" g7 ?1 r ?6 h7 Q4 y9 t
程序例: ) O3 |6 W/ I' b# o6 V, _. Q* |) _# o
#include <STDIO.H>& A: ^6 K7 w% _9 j" Y- H# X; J
int main(void)
5 z* }" R9 a7 F2 g0 h" x6 v{
& }* H& v& j1 s9 F: I9 vchar file[80]; 
6 _* l6 k# {. C* f/* prompt for file name to delete */
; c: X/ y$ J3 }8 Q* s! Hprintf("File to delete: "); ' L# j. a3 V$ {7 @8 N, p$ F
gets(file); 3 G% x# W7 s' N6 |4 H7 w9 z+ }
/* delete the file */ 1 [0 @, f0 a( i
if (remove(file) == 0)
, \) G- g. p) Wprintf("Removed %s.\n",file); ( Z4 t& t0 M) `
else
# a( n* w+ v7 @/ [perror("remove"); 
7 o% f% I' I6 B5 T* ?" Preturn 0;
2 y* |& {' m6 G r}
; v( H4 R' M) H( Z
# f! N4 k7 l0 ~, y) L. e' U- e. ~: g f
函数名: rename 
7 e4 o, d; _5 `4 T功能: 重命名文件
1 c( k/ V: C7 s# O用法: int rename(char *oldname, char *newname); ' @ `* R& a, _# L7 }# D6 K
程序例: 4 q. M9 ]! K2 h+ Y' {$ [$ j2 x
#include <STDIO.H>
 i, J% S6 B* O" L% iint main(void)
: I5 m- d' l3 J{
, D" @; x. x/ o2 z' U( bchar oldname[80], newname[80]; * W- T! d7 L9 A+ n3 S) k
/* prompt for file to rename and new name */ ) r+ p' W$ M0 N/ O7 @: i3 c: T, W
printf("File to rename: "); 8 E( a' V* w9 }% w: b5 \% _
gets(oldname); 2 j' K" x3 c0 H# w
printf("New name: ");
, z/ K* Q7 r- I5 e' P+ ?gets(newname); 3 o3 y3 f; p* u( i: w3 L
/* Rename the file */ ! K/ }9 z( G5 {2 `3 f% T6 { e# |
if (rename(oldname, newname) == 0)
$ @) I6 w! G7 ^3 {& A9 Q/ Y1 _printf("Renamed %s to %s.\n", oldname, newname); : _! C" Z# a4 y( Q& _
else
- m/ U- e# T- Y+ C2 p! ~/ rperror("rename"); , g D# J6 n5 ]
return 0;
' O* w0 c" p1 f9 v}
" `1 b( }; C V9 ?, u7 e7 k ~
9 q# W1 {' H f; h( k6 m. S4 ~- e- `+ e) D
函数名: restorecrtmode 
0 ]- O F2 \6 W0 g- z功能: 将屏幕模式恢复为先前的imitgraph设置 * N) ^5 M( y5 E3 l( s j+ F# S
用法: void far restorecrtmode(void);
! q' j# J) F$ o0 x7 b程序例: 
5 j- O1 f& I2 E2 j/ Z#include <GRAPHICS.H>2 @2 J4 U5 T% V& c, t; Z
#include <STDLIB.H>7 }& A3 u8 g: m$ D! [
#include <STDIO.H>) W* F5 u/ X. U. k' W0 I# t
#include <CONIO.H>2 A( a# z% a/ n7 z- ^) V) H+ Q
int main(void) c' ]8 y, p5 G/ y
{
8 j* T% D! k- S& k/* request auto detection */
# c) k% t& }( P9 N1 @" ^9 ]; Cint gdriver = DETECT, gmode, errorcode;
6 G" A, |# K+ f6 u1 ^! Z, ]4 }int x, y; / r- H( k/ A1 n0 l& g5 u
/* initialize graphics and local variables */ * Q. S3 O; _; N1 a/ ~1 d0 E' a- e# u
initgraph(&gdriver, &gmode, ""); 
9 k% c0 Y. B" s/* read result of initialization */
' o2 \) i: d! G% i+ G4 @. t" _. Y3 Qerrorcode = graphresult(); # _! f6 y- u) _1 [
if (errorcode != grOk) /* an error occurred */ ( W4 v6 D; `5 x h
{
; V( c- O* f& h: z8 aprintf("Graphics error: %s\n", grapherrormsg(errorcode)); & d7 d& J- q) b# V$ M2 b5 a
printf("Press any key to halt:"); : T( n" ?8 v# J3 K) e' a
getch(); 4 E6 O: \& U8 @2 F" E$ T
exit(1); /* terminate with an error code */ , m$ o5 `9 x% J0 x0 s( q" @, H
} 
# M1 P5 q' u/ ^8 _) e% Yx = getmaxx() / 2; + U& ~) G% O2 |4 R+ C8 B
y = getmaxy() / 2; ) Z( V" \0 k+ J! s5 E
/* output a message */
' V; _4 [# A; d7 ~- ^settextjustify(CENTER_TEXT, CENTER_TEXT); - R# p5 W) m1 ^; L
outtextxy(x, y, "Press any key to exit graphics:");
* b$ a" |/ G+ j' }getch(); 
 \- j$ W/ {1 M5 V/* restore system to text mode */ - I& D% Y5 \( T: M' I
restorecrtmode(); p% k3 r- y+ L8 o& u
printf("We're now in text mode.\n"); 8 i; j8 D8 J; U/ L
printf("Press any key to return to graphics mode:");
1 I/ e8 i8 u3 O/ E3 fgetch(); 1 K+ U0 W& M B
/* return to graphics mode */ + r1 P3 F1 q" W9 s8 ?( U
setgraphmode(getgraphmode()); . r' m1 K7 e. p# Z& b. Q
/* output a message */
 w9 J2 F) D# S1 Bsettextjustify(CENTER_TEXT, CENTER_TEXT);
% }3 M( N1 v. U4 Bouttextxy(x, y, "We're back in graphics mode.");
* S* H# `' D# V, d' gouttextxy(x, y+textheight("W"), "Press any key to halt:"); 
1 T9 G- ?/ z9 @4 y' \ R1 u$ S" W/* clean up */
& p3 V' |( R7 K* ~% f* \! Egetch(); ' t0 i- ?5 K, B8 u
closegraph(); 0 y" _% o! B8 v V2 `
return 0;
0 z1 f# k% c E} ) x+ S2 D( o: K: Q

: ]/ V% k: M$ E, u2 V# y( O
5 Y1 R5 G) f/ u2 s9 q函数名: rewind 8 u) F( O) X. V# S
功能: 将文件指针重新指向一个流的开头
, d8 e7 ~/ S( ]; m用法: int rewind(FILE *stream);
# X1 y2 E* s+ p7 w& u! @程序例: 
6 }( q" P+ w6 l k3 G/ D#include <STDIO.H>
, }2 F/ r6 A" Y6 t( k& O1 s* h#include <DIR.H>
- L4 [5 C3 `; ]$ y" Vint main(void) 7 r. q/ j) |2 T1 V
{ 7 E0 j/ T8 q) ]( C" @* e, P
FILE *fp;
+ H8 V+ y. |) g } o7 K0 Nchar *fname = "TXXXXXX", *newname, first; 
% y! P' J/ w9 c# M$ Z5 mnewname = mktemp(fname); $ J9 C; |2 O- f2 k* H% M: y9 k1 P
fp = fopen(newname,"w+"); 0 Y: i* G5 C0 o+ X* j
fprintf(fp,"abcdefghijklmnopqrstuvwxyz"); 1 r0 I% l0 A) c' }3 m
rewind(fp); , v! I# J( K8 C2 G
fscanf(fp,"%c",&first);
+ U3 a) D* S; x1 U6 lprintf("The first character is: %c\n",first); ) ^6 l. o$ o# m& b9 H3 N4 f4 T
fclose(fp); 0 H7 v( u% U0 ~ d# ?1 R
remove(newname); 
0 ]8 P1 ?; d2 [4 e& [return 0; 1 W4 h r/ s4 |! a0 k
}
& r. @3 v% c4 o* m9 P2 \- b. b* w
6 q6 _$ B! `3 v5 q% @0 t) K* x8 T2 ~3 |2 T
函数名: rmdir & K3 _) g3 f5 D# O; Q
功能: 删除DOS文件目录
& B5 {& o8 ~3 W1 L' {; [3 F用法: int rmdir(char *stream);
' m+ Q+ c ?4 u$ u, u程序例: 9 q& r3 h, m/ l5 x
#include <STDIO.H>/ |1 U- Z9 t ^8 z/ |$ b
#include <CONIO.H>
: t. e ]' ~: `" Y* r#include <PROCESS.H>( q) M9 | b. I" h2 C. z
#include <DIR.H>% e: k& P$ I* f/ g
#define DIRNAME "testdir.$$$" 
5 _$ p! T) l* ^! n. Bint main(void) , _& R4 a/ Y$ O; p4 z4 V
{
; z* K/ {' ]3 g3 q' o6 g6 }int stat; 
0 ?! \" x5 q; ~7 a. F) @8 }& l+ Sstat = mkdir(DIRNAME); : [) i+ m1 l# @( m% ^# O
if (!stat) / G6 p* i" U/ c8 N1 a2 r. [
printf("Directory created\n"); 8 ]: K' U% N& c& w. O# w2 x
else - T, `/ N1 T1 K1 s& L* P5 C
{
* D' R$ j3 `+ s# e: I; Fprintf("Unable to create directory\n"); 7 m& h1 c6 ]8 N9 @. V6 W3 M+ l Z! a
exit(1);
/ l% R3 l- ^# L+ H f6 c, [% K} o$ w3 M* S1 ?) }
getch();
$ @$ F! d) @8 |% Rsystem("dir/p");
8 ?9 r1 l; x; e& u. Vgetch(); 
4 j0 s, [" @7 c' |6 |* R* Tstat = rmdir(DIRNAME);
 b* J. r' [& O0 A) L% iif (!stat) 1 D$ d# ?1 |# l( w. a2 S2 T/ T
printf("\nDirectory deleted\n");
5 l$ r$ m9 D6 l2 u/ @6 [else ' w" z+ a5 _/ u8 X6 P# y
{ 1 g M! |7 x1 t/ x; H" R. {
perror("\nUnable to delete directory\n");
; K! m6 s6 _+ e/ Y+ Aexit(1); ( J: O4 X. j! I( Q3 u# g
} 
- u. |: f- M5 {2 s9 Lreturn 0; 8 a" Y. \# A6 p
}