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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 |正序浏览

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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); 
5 x: @! Q P' |+ ]+ L) C2 j/* restore previous dta */ n6 }3 H1 x! i' q, ]
setdta(save_dta); 
6 v: J8 x. Q" Q k' j( preturn 0; 6 C8 w3 J m! B7 D& H7 t9 w+ {( F
} 7 c! v2 F2 R5 `9 V+ W
3 Z3 W$ B3 @, [) f: R: w
函数名: randbwr , b4 f6 d6 u; N( p- d9 e% G% o
功能: 随机块写
1 S6 k! y! R: v! h用法: int randbwr(struct fcp *fcbptr, int reccnt); " y, l+ ]3 c% D. F% P) d
程序例: [) s1 y3 w! C9 d `9 z) K3 t
#include <PROCESS.H>4 n7 y* H! d* l5 \7 x
#include <STRING.H>
& B: T" ]% N+ f2 }#include <STDIO.H>
3 n% t! X, \! v" g2 Z#include <DOS.H>( t- B3 {# }9 _6 O) X( X0 X
int main(void) ) @* o* t2 w. {' A: E( t0 a5 ?; c
{ # v. Y3 X6 k/ i% u
char far *save_dta; 1 |. n7 o+ g* J3 d7 i( w
char line[80];
" v8 k/ @' X7 C2 u" O5 [) a7 lchar buffer[256] = "RANDBWR test!"; - R0 V3 K. l: H; G& q2 T
struct fcb blk; ! F& B/ i9 V5 }1 \# z
int result; 6 g3 D7 L1 c# U( ^
/* get new file name from user */
) f* ?7 U7 h# g) sprintf("Enter a file name to create (no path - ie. a:file.dat\n");
* [9 C& x- D% r4 \8 \) l- r, x7 m7 Tgets(line); 
( ?8 T2 ]" [6 L/* parse the new file name to the dta */ & s \( e8 I2 B/ x. Y2 W
parsfnm(line,&blk,1); 8 A, @( [. U( s3 v+ C6 r4 t3 w
printf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
; @4 t2 b- G Q9 p9 ~0 Z0 G; p. {/* request DOS services to create file */
 g& v' a! C7 Sif (bdosptr(0x16, &blk, 0) == -1) 4 H. G: q- C$ ~% W( v
{ . W+ W7 e ^2 d! H
perror("Error creating file");
6 B1 T9 A" `9 [1 s% Nexit(1);
/ Q3 h+ u5 D& X- t" U} 
! T, [# u& ?/ {" E0 a+ U) l/* save old dta and set new dta */
4 i R1 l6 }0 L5 m4 S/ c9 msave_dta = getdta(); + S* E9 W2 ]$ L: Q
setdta(buffer); 
; p6 Y3 ~: ?' }- `7 I6 F/* write new records */
* U: P! h% X! C3 |' O7 b, ?! H) xblk.fcb_recsize = 256; ! L# b) R' ^' b- u5 G% \! h
blk.fcb_random = 0L;
/ \' n9 S2 X/ H9 x! Dresult = randbwr(&blk, 1); 
8 F1 \/ g0 Y' f* i) N# mif (!result)
) ~) f, L" v3 ^8 k' sprintf("Write OK\n");
' ?+ T) u- Y/ C$ V Aelse
" Y8 T! y6 C" ^* R$ h( X{
' A3 N2 K2 {3 n9 g. Hperror("Disk error"); 7 G1 t5 A4 ^! F4 S0 R7 k5 K B
exit(1);
& X% B5 D' _" g# D} 
3 c! q" w+ y2 N/* request DOS services to close the file */ " D" H, l- H: Y# V9 H
if (bdosptr(0x10, &blk, 0) == -1) ; k; {, m( Y o! J
{
' j- t3 t. E7 e: Z0 v+ A J" q+ Qperror("Error closing file"); N: v! J C. r& ?/ t
exit(1); 2 A' k, I6 T+ B& w- e& z$ ?
} - z, i+ O. D5 J( a: r
/* reset the old dta */
$ u8 e) M5 Q) Q4 f Ksetdta(save_dta); 
! j2 H' p9 H: v, U Oreturn 0; ; B9 h0 }0 {/ o% P
} 0 N4 F: }/ |& g
 x6 O, j6 a1 C3 Q* m S" a

1 m0 ~# y# Q! o函数名: random : ~7 V/ S' E, v0 S3 j9 I! ^
功能: 随机数发生器
, ~! k4 L5 n9 Q9 a用法: int random(int num);
2 Z, h7 h/ p* Z5 d6 o. O程序例: ! l1 {0 R8 q: E b/ K+ M' C
#include <STDLIB.H>; V# r% P8 @% @% c: ~: N
#include <STDIO.H>
9 [1 M& z2 K( T$ r#include <TIME.H>* z# d2 a7 Y9 n; {& Z3 y% z
/* prints a random number in the range 0 to 99 */
, u$ B" H% v# e; Y1 }int main(void) $ `: g+ h- Z5 d9 [3 i c& S
{ ( J/ H- p) a$ n% @, F) Q6 t, t
randomize(); ! C0 ]" I3 m6 b6 Q$ \5 v
printf("Random number in the 0-99 range: %d\n", random (100));
# |* `9 J0 s5 w2 M l$ u1 |return 0;
9 L$ }+ }+ C. v, M9 x, ?}
- K+ ~0 F n6 _* ]! s# L" Z1 s% `* I$ Q2 j; G/ M9 J4 G: _: P- n

- w+ k9 d3 ^$ p0 G* {$ G函数名: randomize 
: T" \- Y3 P4 k. S9 r# a2 d: ]0 q功能: 初始化随机数发生器 8 a3 M4 E6 h" \9 A( P2 ?
用法: void randomize(void); 6 k/ r' y& J0 U6 T/ H
程序例: 9 s# U1 N0 e) d
#include <STDLIB.H>
; {3 \! t' d* F, x( _#include <STDIO.H>
- |- M- h' H8 F6 k6 c( L#include <TIME.H>4 J m* j' [6 U- n7 f6 V
int main(void)
# T! J; j1 T ~3 c" q0 Q{ s, b6 N4 Q- T& h; }7 P
int i; . O0 |; `5 A; p3 A
randomize();
0 _3 S+ E: q9 a/ M/ t( g4 O+ lprintf("Ten random numbers from 0 to 99\n\n");
& u" v% W/ s( o$ E( G$ V0 r, E* ifor(i=0; i<10; i++)
9 y/ ]3 P: v) t. Y9 n0 i$ sprintf("%d\n", rand() % 100);
9 A# q, g" {& t, H; S8 o/ ]0 Xreturn 0; , E% ]. I4 ^4 m P
}
4 X# N7 n- s4 Z0 M, M, H3 q7 j
, F# g1 c" i: W1 T/ \- E$ k/ r' x
函数名: read 6 V+ i" F5 D6 {3 g6 ~7 ^" k
功能: 从文件中读
( p! p4 d" v ?% d1 V& s7 B0 ^; t用法: int read(int handle, void *buf, int nbyte); - i" E! _- ]& b6 H- Z P
程序例: : V5 b8 f8 |5 x# U; ^
#include <STDIO.H>/ T+ J9 X N7 h8 X' h
#include <IO.H>
9 G2 u5 A0 y6 x b6 o. @#include <ALLOC.H>
( n, ~. e6 V, a* x5 H% X#include <FCNTL.H>
( {1 Y7 P0 t4 T4 a# Q P#include <PROCESS.H>
% E" b! i+ R& s: J% S! k' ^7 F#include <SYS\STAT.H>
' m E+ |# v$ Qint main(void) ) g4 M: j1 x) ~+ [) P: q7 h
{
, X5 y7 t) {/ H9 v/ a, O' Uvoid *buf; 8 L8 L7 I, f. f5 o
int handle, bytes; ) b4 q7 r$ u! }2 G5 B* f8 {( d
buf = malloc(10); . i: M. v+ H% Z' _. Y' g. [/ C
/*
3 }. \( ^3 I3 Z/ }# eLooks for a file in the current directory named TEST.$$$ and attempts
, A: ]$ [) C; U; \, V4 p# G; B8 hto read 10 bytes from it. To use this example you should create the
( D& i% E% B9 K: T+ L- Bfile TEST.$$$
' w' S" h1 G9 K' ^6 |1 k*/
* h |8 ?8 M* p8 oif ((handle = 4 V0 n6 B0 S) q/ \9 A1 |2 R
open("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1)
# E$ t5 S2 N" K0 R: o+ p{ - v( i- ]# d8 J
printf("Error Opening File\n");
8 `. }; A+ f" X8 ]# n8 M6 Kexit(1);
& u6 K, n; q# A1 w1 B8 p} 
+ b4 ?% Y% A. b8 Q! Dif ((bytes = read(handle, buf, 10)) == -1) { ! |& a. n9 t) B+ T
printf("Read Failed.\n"); ) h/ d+ g! j$ F7 h
exit(1); ; v. B0 ^3 l% G/ ^# A& S
}
1 i6 k7 c0 h( ?5 j1 n1 W; x1 @% Yelse { U3 H& C; t0 I+ _' Q
printf("Read: %d bytes read.\n", bytes);
4 [$ E2 b" t% r' `' S7 i}
! A1 C! O2 E4 H2 D/ K7 Q+ ^return 0; % _/ d9 K$ M7 s' Y6 |
} 
" ]1 [, q6 _+ x9 U9 m( f
* I: X h9 {& O+ m
. ^$ E0 h9 B% v" ^3 a; }( {函数名: realloc 
 t+ D) Y( d' |- E# M- ]功能: 重新分配主存 $ f7 Q2 H( L7 I7 I: J7 \3 [- G
用法: void *realloc(void *ptr, unsigned newsize); $ D1 }4 b. m" v0 H3 K6 {5 o( |9 O! E
程序例: 
" o2 ~; V/ ]5 @/ F; D% T#include <STDIO.H> v- n% V6 E |/ u# W ?! U% P
#include <ALLOC.H>
# x& T$ l$ _; [7 |+ d#include <STRING.H>* n& ?5 ~; A) I/ T5 @
int main(void)
6 G5 ?8 K! T: _8 E) }{
; G2 A" Y$ _0 g0 @8 B8 a# Wchar *str; , E- Z$ n3 o2 J" |) n, `
/* allocate memory for string */ ; B2 [ t! ], ^! ^7 X
str = malloc(10); * i. S7 m9 U4 [" Y9 n3 _
/* copy "Hello" into string */
$ l. \+ e- [; bstrcpy(str, "Hello"); # w6 d( \! ~" y
printf("String is %s\n Address is %p\n", str, str); ) n& l/ k9 n% c/ G& f3 R4 I
str = realloc(str, 20); $ Z) p- @6 p: r! H% Z+ o3 @" r# G
printf("String is %s\n New address is %p\n", str, str); 
8 H6 W+ }. q' v) L: X& K/* free memory */ ( a9 c* [( E" T4 K+ {. O
free(str); $ i3 L* E1 ~4 ]- x% q8 u
return 0;
% F8 F6 S5 o% `& @# A0 M$ t" @2 `}
& c M- e# e% [; N9 i; X% s. q+ u U8 r! V0 z6 x
8 O! M. k+ h! a+ B0 q8 E) r5 P! x e
函数名: rectangle 
2 I, c; c* I) f4 q) U' ^0 x! z) ^功能: 画一个矩形
 ^% e3 j1 d( j% B1 k: E; ]用法: void far rectangle(int left, int top, int right, int bottom);
6 {+ e6 R3 v6 Y9 c" X8 x程序例: B- L/ G5 d' l2 z
#include <GRAPHICS.H>1 Q; h! Z! P* c* j0 _: H& O
#include <STDLIB.H>! q7 A# g" a: c+ w
#include <STDIO.H>
1 U% I7 ~( {: }; I$ `7 D#include <CONIO.H>; w4 w7 E* R: b$ q
int main(void)
* v' q" ]! \7 ~7 Y; ]* L! r |{
 a% Z( c" W1 b" W) j" I- h/ j! S/* request auto detection */ 7 H+ L: G f4 ~' U( q4 r5 p
int gdriver = DETECT, gmode, errorcode; 0 |; {+ y$ u& f1 i+ F
int left, top, right, bottom; # Z9 R+ S: E9 z! ~
/* initialize graphics and local variables */
( j1 @3 a" y( m0 i% Jinitgraph(&gdriver, &gmode, ""); 2 p) ?0 }5 \1 I! f3 U9 m+ d
/* read result of initialization */ ( c" H# k6 _5 L2 r: y
errorcode = graphresult(); ( E; P+ M3 M* a
if (errorcode != grOk) /* an error occurred */ + M8 z4 L/ ~/ E& {3 A% ~9 g5 K. P0 s' F
{ , F( t' B% O& \9 H" N# i8 u
printf("Graphics error: %s\n", grapherrormsg(errorcode));
& Z! `7 e% M1 @. f6 qprintf("Press any key to halt:");
 e& v! n$ B8 p/ Q7 |" Rgetch();
3 `' f) q1 y, Wexit(1); /* terminate with an error code */ + K2 \: D5 Z1 e! p' V9 L
} ; S$ V& k8 O( b4 @6 ?
left = getmaxx() / 2 - 50; & I% u$ B3 y9 m- f
top = getmaxy() / 2 - 50;
' z- B- y3 q' ^0 n$ U) Y" Q- cright = getmaxx() / 2 + 50; 8 ~/ b: e: V" a9 G- l1 q; ?
bottom = getmaxy() / 2 + 50; 
) d2 T3 i- f* f% q/* draw a rectangle */
. K: T4 B; _0 W0 Lrectangle(left,top,right,bottom); 
8 o0 {2 B9 v- [/* clean up */ / w2 l) j# c: R* D) G
getch();
. q6 \! A7 p/ n1 Bclosegraph(); % H$ z7 |: B+ `0 Y
return 0;
5 p1 k0 x7 \8 g0 Z4 H} " x H" F' T# R% A* X$ n( z
) x* |( @$ H1 o- x

$ c$ O7 L, [ a! L$ N* Q' k: D+ g3 W函数名: registerbgidriver 
- ~ R, m$ d7 S4 N! L$ G. a" z! Q+ s功能: 登录已连接进来的图形驱动程序代码 * P" s7 B4 k. V' U. ~1 {' ?
用法: int registerbgidriver(void(*driver)(void));
, w9 n; H1 ~5 j$ d; F q+ \4 v程序例: 
: a# B% ]% h1 i6 G* c- k9 v#include <GRAPHICS.H>
 U( \' ^1 f* n& Q) O. q7 ?, ^! P#include <STDLIB.H>0 ?# v0 w9 R# C" u9 {4 @, a) _
#include <STDIO.H>
& p7 P+ S1 A# W* m& ~9 @#include <CONIO.H>8 F2 A, b- [, z7 s+ R/ U* K. |5 M
int main(void) ' d* v$ I6 W) m" l
{ 3 `6 I( ^: T3 ~5 L4 V% P. ^
/* request auto detection */
0 s! Y0 K4 k& ^) I1 u. K6 b7 K: t+ hint gdriver = DETECT, gmode, errorcode; ' r5 m, S, G( l0 X( d E: J# w
/* register a driver that was added into graphics.lib */ ; ~; x& g& ]! S4 r( Q% s F& c
errorcode = registerbgidriver(EGAVGA_driver); 
, e2 n1 O6 U. m" S4 d" Q+ ]/* report any registration errors */ * ^* r5 v0 l5 ]- ^2 Y
if (errorcode < 0)
% h# X: n6 ^0 O+ T- z. C3 a{ - [% g3 k# v& A' j1 |! [: B: S
printf("Graphics error: %s\n", grapherrormsg(errorcode)); 8 H7 N0 \: g5 A; U5 W$ x2 N' t
printf("Press any key to halt:"); / T) n [( S5 \
getch(); 3 L+ U, q6 p9 t! u
exit(1); /* terminate with an error code */
6 J' ]+ N$ ]# K/ x; ~& j- R8 P+ t5 z/ K} 
$ a+ x: L: ^' w& b/* initialize graphics and local variables */ & v( ]+ x: p0 x2 ?9 S% A
initgraph(&gdriver, &gmode, ""); 
1 @3 d! _3 p; }8 w8 p# m/* read result of initialization */ " r9 g- S: D/ R- Y9 |
errorcode = graphresult();
; X6 k# z4 c- m# s# e# @+ q( P3 Dif (errorcode != grOk) /* an error occurred */ - l1 h2 I$ n0 I$ s
{ 8 X" I& V! f, _% R" s6 D
printf("Graphics error: %s\n", grapherrormsg(errorcode));
# w, i9 s& M" j/ cprintf("Press any key to halt:");
, H& D. ]# u% }( H' [getch(); ! j8 Q, {4 H' B0 B6 n! F
exit(1); /* terminate with an error code */
8 q `8 G' G# Q- K} 
! }% b9 X* {& f) U- ?- K+ O/* draw a line */ 7 E F r8 E d/ C# t, F% F
line(0, 0, getmaxx(), getmaxy()); 
5 h6 {- H2 v0 G3 V% [+ c) O' Z/* clean up */ + ~& B' W( ?# _4 D% Z* o+ P
getch();
3 v- M& j7 q/ _8 ~. ^closegraph(); + y$ q2 B1 P' e0 L. j+ }
return 0; 5 w. @) e+ P% v; n" S9 O
} $ h, j7 j# _: f5 D4 b3 T
) [, L P* F- ?# K$ T0 ~

, M. Y2 l5 `4 {0 ]0 m函数名: remove 2 w$ N6 P/ g' v4 O# _, S' j
功能: 删除一个文件 ) R# N6 T- E& N+ s/ [4 B, J6 s
用法: int remove(char *filename);
; B8 I8 }6 z8 a$ M# f$ H程序例: 
2 L7 K6 u0 Z% Q, |8 t6 ?3 p#include <STDIO.H>; B" T' d3 D/ g
int main(void) 2 f; a2 {$ g, k6 K' \/ G7 i+ P
{ 5 P( a( @0 Q" O9 |
char file[80]; 
0 H/ J% _ }) ^: V5 g+ E/* prompt for file name to delete */
 z5 \, ?" @2 H0 E; Rprintf("File to delete: "); ?( ^( h' o& e+ |7 i# a4 Z
gets(file); ; S) c' {! E7 W, E8 E) z
/* delete the file */ 1 x! q7 ]0 x2 o6 X! O
if (remove(file) == 0) ( T' ~5 j; u$ c' F0 v& i- h
printf("Removed %s.\n",file);
7 k) v R3 y, R& q# Qelse
8 b0 y# [, g+ {# i! d6 z& G) Z( X& Q* aperror("remove"); 
, ^, L& n, H: R: N: { nreturn 0;
) e5 X& n! N. ?- C8 d* ^4 X d}
/ b3 T9 k3 ~+ y N2 K: m8 V2 q7 s) S) _7 b
: W- o5 E2 g$ }" v6 z* D5 S) R9 `
函数名: rename ) X3 }' O, w- L( P
功能: 重命名文件 4 o1 K/ G |! `2 Z- a$ x
用法: int rename(char *oldname, char *newname);
7 h q( y: ]3 W' g& |2 S5 V程序例: 
! h% l9 G8 c# n: r- }' p# E#include <STDIO.H>5 E& x) Z+ z4 G- X8 s
int main(void)
: ]+ O8 v1 ^6 l1 }{
( f; c9 {* d Lchar oldname[80], newname[80]; ! I0 Q: U1 y6 P, r& P6 L& w
/* prompt for file to rename and new name */ 5 F/ w) O d! O- j* e- \) r6 K, u6 Y5 O
printf("File to rename: "); : }) d1 c3 f5 G
gets(oldname);
 v% u" R: A7 x* i% oprintf("New name: ");
6 ~, c9 c3 ?$ h$ @+ Qgets(newname); 
' r/ V; Y9 Z* L0 Z5 v4 d/* Rename the file */ - m' W# O |" X6 b! \
if (rename(oldname, newname) == 0) 3 o1 X4 k; | J) ]6 r
printf("Renamed %s to %s.\n", oldname, newname); 9 v+ f: t, x3 g$ R) t5 \
else 8 S; ^9 o) i* Y6 j4 p
perror("rename"); ! m, t; P% K' j9 ~1 ~, M
return 0;
& Y8 l5 q! p8 C1 B} + B4 E* p2 Y) B
! w+ p( u6 V* C$ D. a

& ]8 x; M* ~, I8 C4 K3 `/ L% V. C. Q函数名: restorecrtmode 4 g# e8 f. Y. e' t" Q/ w
功能: 将屏幕模式恢复为先前的imitgraph设置 - T5 h3 [; _) t& K: [$ y9 V
用法: void far restorecrtmode(void); . b: s* t/ k, K0 C1 c
程序例: - e* ?' v, H- X( A2 J( p
#include <GRAPHICS.H>+ V" D) K4 x; b9 I; m4 h8 e
#include <STDLIB.H>
9 ^8 b* b3 w* R" u$ s) `+ t#include <STDIO.H>5 p' \" L2 H; _: q b x
#include <CONIO.H>2 L: i3 ?/ Q9 W; I) V& _# E" S: x
int main(void)
# k r ~; A% g$ D& f{ 1 x1 @+ s4 T- A7 b; b
/* request auto detection */ * L$ m+ Q7 b0 i
int gdriver = DETECT, gmode, errorcode;
! M6 W/ k% W! Z; S0 V! f; Wint x, y; 
, I7 b. ~$ ~; w% s/ o/ R7 b- L: [5 X/* initialize graphics and local variables */ 4 H, y) E$ z- z2 E7 }' \+ [. R
initgraph(&gdriver, &gmode, ""); 
, O" j: j- @! J3 R* Z( `, `/* read result of initialization */
: N7 J' j. k6 L# g1 y5 X+ ierrorcode = graphresult();
, y2 D3 d9 ?6 h- k. m' ]9 ?if (errorcode != grOk) /* an error occurred */
) U% g2 l* ^6 _; a/ R6 }{
6 K6 @* t' A. W9 R9 ?printf("Graphics error: %s\n", grapherrormsg(errorcode)); ( D* b6 g7 Z; W3 h7 B6 S
printf("Press any key to halt:");
! _1 x0 p/ J" Z: k1 i. Ogetch();
$ K3 W1 N+ t; U; J* b( u4 Uexit(1); /* terminate with an error code */ 1 x7 t# X/ Q; W8 I
} ; j1 q" N+ `" L, Q/ a5 n
x = getmaxx() / 2; ) k! v3 u. [6 B. a7 R# Y
y = getmaxy() / 2; 4 A8 ^6 v; W4 P" Q* @$ Z
/* output a message */
8 ^3 k/ c) G+ g; T, o: O ^) a: v( hsettextjustify(CENTER_TEXT, CENTER_TEXT);
6 T& g* O0 b/ X2 D- [/ r, Wouttextxy(x, y, "Press any key to exit graphics:"); * }4 F# q( L1 E# s5 m
getch(); 3 U' O( F7 I; I/ k8 N' T; l
/* restore system to text mode */
' k! E/ H8 V8 Y- N* Nrestorecrtmode();
, x4 s& S: H( K/ o! S( ?# qprintf("We're now in text mode.\n"); " E; @6 o! I6 |# ^ L/ z
printf("Press any key to return to graphics mode:");
7 R: y6 f8 o8 S* G0 Cgetch(); 
# `% {( c; h* @/ H( D/* return to graphics mode */ , Z2 u6 P! c! v t
setgraphmode(getgraphmode()); 
+ P+ V; O- }6 e! Z0 X/* output a message */ 6 z; G* l: t% g8 u0 |: N! Y
settextjustify(CENTER_TEXT, CENTER_TEXT);
4 [) b0 W) h* Y' c- R( I, aouttextxy(x, y, "We're back in graphics mode."); ' l& }# ]: q& P t e
outtextxy(x, y+textheight("W"), "Press any key to halt:"); 
: n D; `& m: E; N1 z# m+ z/* clean up */ 6 m- t1 ^" y; X' b3 U% @6 S+ w' M8 i
getch();
4 I g3 |( b! ~8 z% O8 Yclosegraph();
" t7 V$ c" P/ Rreturn 0; , O, H" b# s) l8 A& M
}
7 H2 w% F3 g0 M! x( p
" L9 u* o; D6 T9 G& |0 J' A; i& j) b3 z0 N4 M7 H% W6 U2 x3 [
函数名: rewind . x: C6 _ r7 J
功能: 将文件指针重新指向一个流的开头 + U( _) q. p; _- X2 m) j- F
用法: int rewind(FILE *stream);
5 A8 Q# C) _* f/ r2 S程序例: : H! {1 R, M6 A8 i7 Y# [
#include <STDIO.H>
& F( J8 A& N* v0 K8 b9 e#include <DIR.H>5 N8 r9 @$ x6 Y
int main(void) $ p3 B* H. q K2 M3 m
{
 M( d" x- s4 @ p2 v' |$ QFILE *fp; 7 i" R; J, c# X8 w8 e" _& n
char *fname = "TXXXXXX", *newname, first; 9 E2 Z' N5 K! y% t
newname = mktemp(fname);
" C$ B* u8 K/ T: O% i$ a4 I/ B9 Q) Gfp = fopen(newname,"w+");
8 A: ]6 F0 C- P- O. E, Dfprintf(fp,"abcdefghijklmnopqrstuvwxyz"); 3 Q9 O4 l+ `6 p: y! G. ?
rewind(fp); 8 W" N1 `7 Y/ t a+ m, ~, ~/ z
fscanf(fp,"%c",&first);
" z+ ~- ]5 Z( p9 B1 hprintf("The first character is: %c\n",first);
, ^; E9 p0 n& U/ ], xfclose(fp);
+ R8 g+ ]5 \4 \! ~remove(newname); 3 D* N. ]* L9 P: ` G6 H/ b
return 0; 8 P [4 z% |( S2 j) v
} ' i8 F e2 Z2 Y- X9 j- t6 |

1 z- s2 @" h. t& q k3 @( | t8 t' y3 w4 r+ q
函数名: rmdir 
/ Y- r6 |1 D9 Z2 t5 e功能: 删除DOS文件目录 4 U, ~ H A+ f+ o$ P. a" R; v* |% v Z
用法: int rmdir(char *stream); ( R( m" k+ o2 x" C( D& R
程序例: 
/ t, t& o) q# _5 Y6 H/ O+ R#include <STDIO.H>/ X% V# v l* e- L$ [9 A
#include <CONIO.H>
% R% W+ ^& B* F0 w) k+ e( P#include <PROCESS.H>
1 ]5 j; p' B* C$ d#include <DIR.H>; m9 M0 ?0 j' Z
#define DIRNAME "testdir.$$$" ' e4 j5 P" u+ c) ~/ c3 ]( z
int main(void) / u/ f- w$ ]; M1 z9 r# h
{
/ s6 ~3 E( {; g ]. Hint stat; ; T; d% D: V/ n" V
stat = mkdir(DIRNAME); ) c* X, m% s- ~% B0 c1 p, h
if (!stat)
) J) s, f: ^2 D: t9 Gprintf("Directory created\n"); ' Z% J/ e) w# H, g$ t6 }' J* l& Y2 V
else
. R! ~. J. p! C* B7 }{
- \) H) K( h7 Z% b5 Vprintf("Unable to create directory\n");
7 p+ j7 l( p! J7 V! T. T* w; xexit(1); 6 i* p) {, d. h& y& g7 P, A
} 
2 o5 |: c( P9 ]3 }5 i* Tgetch();
$ C" c7 |9 |% c6 asystem("dir/p");
: ~8 J7 P& E! N3 H; {0 `# o0 ?+ Tgetch(); 
& h/ C4 N" t) L$ ?stat = rmdir(DIRNAME); + h- R8 J7 P; j5 v Y# [" G) Y: B
if (!stat)
7 W k0 S( S9 R0 A; _8 G2 X9 tprintf("\nDirectory deleted\n"); # |0 P' O5 Q$ P0 J# R
else
0 G- K1 f4 D6 u3 x# r1 a2 v{
4 x. M: z2 I& i& I. uperror("\nUnable to delete directory\n");
1 J$ @1 z; s" z1 g! T7 Q4 `, @exit(1);
" p' b' S5 H! ]7 q} 3 O4 V: R, x$ R+ |8 S
return 0; 4 g) j. b' S! _: Y8 a0 B
}