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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); 2 D9 v; [! X' g& ^: a" q; e. a$ ^
/* restore previous dta */ % j7 R) {2 q4 I
setdta(save_dta); , Q8 m1 u7 Z% `: s' ~( n6 x3 w! u
return 0; % b# n8 y$ Z9 s
} 
: z9 K% l% Z1 [8 {
) J( ^0 s# `) V& ]; s. R函数名: randbwr 4 ^7 }& q. _& N' U6 @
功能: 随机块写
! _& J+ V, v" S+ H; z) {用法: int randbwr(struct fcp *fcbptr, int reccnt); 8 ?8 H' B4 T3 v1 z
程序例: 0 H2 K9 x0 R3 i' ?( ^
#include <PROCESS.H>! m6 Y1 {$ i3 ?5 p, A; q. D4 S% W
#include <STRING.H>5 E7 u0 a. l' U
#include <STDIO.H>, w- g2 e9 v; {0 J. f+ s$ @2 z
#include <DOS.H>
4 ?" Z) X" B }- d jint main(void) 6 ~: ^) z5 j, R
{
% U, P$ a6 n- L% a3 s+ pchar far *save_dta; , y3 O+ V- ^+ h, O+ A. b
char line[80]; 0 {* v3 n. r- f V2 `- n
char buffer[256] = "RANDBWR test!"; - P& l1 \& ~+ @8 w m
struct fcb blk;
5 C1 L' l, B- V' c. Y. sint result; 
! [5 O! V% {" ]0 Z- f0 Y) N5 f/* get new file name from user */
% U3 u& |0 n; {- h: V7 Mprintf("Enter a file name to create (no path - ie. a:file.dat\n");
& `3 ~+ m. K' @, z8 l) Y% H' jgets(line); 9 }" i2 T4 j" A
/* parse the new file name to the dta */
: ?! y% O- u( k) h ~. @( sparsfnm(line,&blk,1);
6 i, L5 Y) ]9 q: Z" F1 W1 jprintf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
+ D3 v, S7 r( Z: y* m/* request DOS services to create file */
* ~9 o0 \5 B4 l! g' `7 ?if (bdosptr(0x16, &blk, 0) == -1) / g" A; E4 M( |) [' z0 u
{
0 a$ k: A6 V+ d1 a6 Gperror("Error creating file");
4 \) v" ]" e& k: j4 [/ Q }" vexit(1); * l. c3 G$ {: d! M$ V: Y' C! _
} 
) H) j1 L& N0 p2 M7 C/* save old dta and set new dta */ 7 d% k2 k) X {+ j5 h- o% r1 z; J x
save_dta = getdta();
' @; ]+ Q4 s' Y5 }setdta(buffer); " b7 O7 t5 w3 _
/* write new records */
# J: K3 f1 W0 r' p# Q/ l& G1 G" Ablk.fcb_recsize = 256; ) J4 H) @# D H" O M
blk.fcb_random = 0L;
; R! f) M6 u( y* Q+ Vresult = randbwr(&blk, 1); ' t# J9 q0 t' W1 T, c* v$ s
if (!result)
: _$ E, A7 |8 X+ \4 W9 Sprintf("Write OK\n"); ; G5 t# X# h( h$ ~3 b5 i7 }
else
, v4 q/ \ \: e- [ ]{
8 |. }! R3 s! y+ y4 Iperror("Disk error"); + O3 }( J* t6 Y2 {8 S
exit(1); ) y. _# I" L$ T* i7 l$ k$ J
} 
( X% i1 Q+ _. {, H# ^/* request DOS services to close the file */
, e/ [$ p0 Y0 Xif (bdosptr(0x10, &blk, 0) == -1) ' U5 x* k' `2 A+ Y: E8 ^
{
3 P0 ^+ T& F( X. s) R: Wperror("Error closing file");
, l; t) r) {6 [" k; wexit(1);
/ C+ V4 {* l! Q" b0 c} ) t- ?' I' v1 G. a* [9 R7 p7 y1 r
/* reset the old dta */ 4 I, }* U: G" r% m' r; ~& f2 p
setdta(save_dta); 2 I& y2 o3 a* R o; Z
return 0;
: f8 J, z; D" O# a" }2 m9 G} - V! ?/ i% ?" Y0 C" w
* ~& k* C) O `7 e# k( d; k

$ \/ _+ z5 \1 K0 n$ j2 ]函数名: random 5 L8 }' x. I5 T$ b# b7 Y
功能: 随机数发生器
8 ]6 p+ M1 o' q8 y$ @用法: int random(int num); , I4 E8 A K8 t! R/ ^$ V% n
程序例: $ g: d/ A. r4 Y
#include <STDLIB.H>, d9 R% i3 x& D, g$ c: h$ Y
#include <STDIO.H>/ H- [( C7 ?$ ] z5 c3 k
#include <TIME.H>
7 i& {/ `2 T, o3 m/* prints a random number in the range 0 to 99 */
+ l. k4 X% Y6 \& D9 vint main(void) 8 O9 c8 r2 l! a! W
{
$ c' Q0 d; O+ i Grandomize();
! }0 v& f2 x9 b; l$ p6 [+ @printf("Random number in the 0-99 range: %d\n", random (100)); $ m; q4 |+ O' m8 _5 Q; m4 X2 M
return 0;
5 V$ q% H( f# r* ?* i2 X$ J} 1 _1 K' ]( G* T( f q5 r. \7 z" b

8 W& z) [2 _" e+ t3 e% x) T: O4 I2 \8 Q
函数名: randomize 9 ?% U, B: W. k2 @. Y5 {6 a. ^
功能: 初始化随机数发生器 # C7 e% j0 j$ q7 A
用法: void randomize(void); 5 Z$ e+ Z( a5 p0 c/ g+ {1 H- J
程序例: 5 J4 c# V, M, @
#include <STDLIB.H>
- J% q. a; y2 d O9 ]#include <STDIO.H> z. f# g( d; C/ m+ G+ ?
#include <TIME.H>2 _) p0 F6 {# {" n
int main(void) . g T" N$ w/ u3 A+ A0 D$ @
{ 8 A# j/ e3 [( W; K
int i; # z1 R& @ x: a1 q' O
randomize();
9 t6 Q) `3 j* x+ k s* s( d, xprintf("Ten random numbers from 0 to 99\n\n"); ) l! H+ ~$ z8 X; [" @7 u/ ]
for(i=0; i<10; i++)
$ L9 h4 T- U- R) L7 Aprintf("%d\n", rand() % 100); % \, D6 q. B# x* q2 I9 H
return 0;
; V2 A( C1 M, C" }6 O5 R}
2 }, W' `; g: ^
* E8 N/ v8 N9 ]4 {: L0 c$ a1 w v3 H5 ?& G
函数名: read 0 X) n. N: ?! ?& Y
功能: 从文件中读 $ b" C; b' J' x- m$ j3 w
用法: int read(int handle, void *buf, int nbyte); 2 e) l, j" b0 B+ M( ? q
程序例: 
: @) s/ |( h0 A1 N+ @# O#include <STDIO.H>
5 u0 y& y% a: R& n2 T#include <IO.H>1 l3 |% O% J3 w* F. J
#include <ALLOC.H>
# n* z* t& O4 p5 G6 S#include <FCNTL.H>4 _2 m+ N6 q! e
#include <PROCESS.H>
9 b3 i Q6 I4 a; t#include <SYS\STAT.H>6 ^3 C3 {/ T, Y6 h% x4 |
int main(void)
# Y/ h h* F. U$ T6 s, D$ r2 {{ ( y8 x' H, D5 G+ R2 z1 l
void *buf; / S5 k$ e% W7 Q0 r6 W R9 r
int handle, bytes; 7 Q0 w. h% q+ ]* [$ |
buf = malloc(10); 
/ N2 J( Y2 r; o6 I& T2 |/* # O) V) g. \6 X3 C: m( \ }& r
Looks for a file in the current directory named TEST.$$$ and attempts
: |5 |% ]$ I! r" J0 dto read 10 bytes from it. To use this example you should create the ; y* [3 i, y/ L W- }- e
file TEST.$$$
1 J+ z! v+ l! T*/
2 i- x# f9 ?6 ^if ((handle =
$ f2 W4 \; X# f6 Popen("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1) + d" O! b- u. ^
{ 3 C9 t/ ~, _4 Y6 e" l
printf("Error Opening File\n"); 8 f; c. P2 m% Z' X1 W/ q, |5 r* }0 U
exit(1); 6 j8 P( o$ u, K; N. ]; j$ e
} * Z( W* g1 [9 s7 E* {( e/ Y) A
if ((bytes = read(handle, buf, 10)) == -1) { 1 e& G% f% q+ P6 X- E, z3 Q: \
printf("Read Failed.\n"); & P# D1 s" f7 e8 o
exit(1); $ {& O6 p3 _' ~! o) }3 s& {! v4 I
} ; H+ X2 }* h' i6 Q
else {
" ]7 t* h( T6 r! y2 k- Wprintf("Read: %d bytes read.\n", bytes);
" k: w( t3 o$ h5 Y4 Y1 z, r} * `1 H4 ?+ x. K" H) o
return 0;
$ ~2 h4 @) [9 \! ?0 y; F; h} 
+ c0 H5 b) y& _: {# {( L1 ^# x8 ? M

, C- O4 T" U1 \2 `: Z- S# P函数名: realloc ! ~7 f5 V) ]3 A7 W; s1 R5 s
功能: 重新分配主存 7 ?# X i) t1 T& ]+ f; L. H3 R
用法: void *realloc(void *ptr, unsigned newsize);
: R, _+ ~9 P I程序例: 
! b Q6 b1 P) \* L+ [#include <STDIO.H>
. W( ^4 ?1 ~# D2 t#include <ALLOC.H>
% h1 X7 X) Z2 U; U6 m: o+ n% `#include <STRING.H>
$ P; f! `* M, i! Sint main(void) * k+ R) Y; m" N6 B/ X3 ]' S
{
* e" l9 n* v1 y2 D" Schar *str; 
2 D' d" J" E v; V6 K$ o: c/* allocate memory for string */ / N& |! G, q2 c0 R% w* e- w8 m
str = malloc(10); 8 U: V6 P. Q" w9 @0 P0 M, r! h7 i
/* copy "Hello" into string */ & V! E9 }: K2 `8 A
strcpy(str, "Hello"); 
$ W. F- ]$ _$ I9 F4 B) `printf("String is %s\n Address is %p\n", str, str); * x! O" d! R; l; u( g" o8 @8 M7 \# O
str = realloc(str, 20);
. I& p! s3 w: J' M& uprintf("String is %s\n New address is %p\n", str, str); % n- Z8 @( f, _' V* x- j* c
/* free memory */ " ?1 l+ d$ {! A7 u m; n5 G r: m4 t
free(str); ; Q) h( U& R( Q s3 _- |
return 0; 6 W7 n0 g% y: c
}
6 m$ C: Q1 s; v$ K/ K
' ~& F W% q V3 k& R: M" I
# S1 C2 ^2 m/ W; |# j) f' f, m函数名: rectangle 4 z0 z- w/ P/ w9 L0 Y
功能: 画一个矩形 4 s* A. `* y' k- J
用法: void far rectangle(int left, int top, int right, int bottom);
4 M: U/ B$ o5 s8 k. t程序例: 
$ i. \6 V6 ]( S4 f) F. ]& \6 l& H#include <GRAPHICS.H>
' W: z* t! K Y, p" u% O#include <STDLIB.H>
# Q# g8 m8 C6 n6 b+ @3 E9 m. h#include <STDIO.H>3 h$ V y6 V! m) Q" C+ N: S$ ^
#include <CONIO.H>9 p; i/ ?0 C$ ?+ K
int main(void) 5 {3 U! ~4 Y# [1 p r
{ 6 s( E* [% Y. ~$ ~* y+ c
/* request auto detection */
9 p8 k6 a6 y6 F( `3 g }4 Lint gdriver = DETECT, gmode, errorcode;
 }5 [& G; _2 O8 {+ g5 _2 D* Rint left, top, right, bottom; 
8 P5 j6 U3 F1 U- O) D/* initialize graphics and local variables */ + V7 t! c" \+ \0 c5 H3 F
initgraph(&gdriver, &gmode, ""); 
6 T' u! V( G% k& B% n' z( h/* read result of initialization */
' l0 Q& E8 M9 q3 w( G2 herrorcode = graphresult(); 0 n2 W3 w* A5 ]% g% F7 R4 l
if (errorcode != grOk) /* an error occurred */ ; z* C9 O' x7 l
{
6 n( Z: t& p0 n" F& rprintf("Graphics error: %s\n", grapherrormsg(errorcode));
9 \5 ~% h( X) w7 o: F/ _5 ~% U) Xprintf("Press any key to halt:"); ) I3 j5 ]- ?+ g% f4 j/ C
getch();
: x% m4 A+ {$ E+ y. rexit(1); /* terminate with an error code */
6 N# }( a( A: X4 H& Q} $ C h# i4 J6 h, R6 X3 r3 W6 o
left = getmaxx() / 2 - 50; " t7 {5 _; F' X+ |7 o# |
top = getmaxy() / 2 - 50; ' c9 M& h( c; a
right = getmaxx() / 2 + 50; 5 P5 A, ?/ V$ g3 _% u: S
bottom = getmaxy() / 2 + 50; 
$ U8 R* A2 T* N" \/* draw a rectangle */ 8 s$ \8 O, F2 c% M; B) u# \ ^
rectangle(left,top,right,bottom); ! ~# [* @# y/ L& D( C
/* clean up */ # P- @* {( ~: a! E2 N
getch();
: I( y- J( I! H2 d. kclosegraph(); 0 R/ Z1 m. T" f# [( r
return 0;
/ y9 L5 D( n$ ]4 a. X}
+ E! j8 I' B+ A( F5 J; o. v" W$ D; C/ w" n# G. a0 |. j7 ~

5 G! o" `. j8 k函数名: registerbgidriver 3 J) h2 p9 E" ~" q! A6 V: p8 a
功能: 登录已连接进来的图形驱动程序代码 . H. ]' G7 O/ e: o4 r& U
用法: int registerbgidriver(void(*driver)(void));
, _3 q% v/ v7 M+ Z程序例: ; Z2 w* X2 ^- G0 P/ B$ B8 B" I
#include <GRAPHICS.H>
2 ~% N9 `5 w& V, K W% h# m. Z, H#include <STDLIB.H>
3 D- }# S! F6 D0 e; _* ?#include <STDIO.H>
! H4 b5 \! @; b* [% F( E#include <CONIO.H>9 Q# Q! e. I. Q
int main(void)
# v' a. Z1 H4 Z8 y( G' J( h{ 6 O& B' l- ~) y8 u% {( {9 F
/* request auto detection */ 0 \) M8 R$ D9 o+ X. {5 {; l
int gdriver = DETECT, gmode, errorcode; 0 H5 V! J7 _1 Q' d2 I5 p4 b
/* register a driver that was added into graphics.lib */
+ G: P# p% o, p# N# |1 Q" O( Herrorcode = registerbgidriver(EGAVGA_driver); 6 G$ S; B9 n' a0 t5 ^6 M% L1 t
/* report any registration errors */
2 [3 y% W0 z1 Y# H6 Vif (errorcode < 0) 6 ^$ L9 \0 T) }
{
5 N; \. {& `" ^4 }0 _printf("Graphics error: %s\n", grapherrormsg(errorcode));
6 K- ^1 m1 R6 X2 F) m1 oprintf("Press any key to halt:"); 8 [3 A2 w7 z: `! ?8 z
getch(); # @- E" L" }! q; n0 q
exit(1); /* terminate with an error code */ ! U1 i: ~, U# L: I( o
} " ]" g. J2 a. R% E8 a( [4 J
/* initialize graphics and local variables */
; m5 P, I. l* Y7 R" M3 Zinitgraph(&gdriver, &gmode, ""); - Y- C! ]/ e Z! c$ v2 c
/* read result of initialization */
& v* b3 y& o. j/ s8 C5 Herrorcode = graphresult();
4 m1 V" m; ^4 cif (errorcode != grOk) /* an error occurred */ ( `; z0 {- R; X" f+ a) B3 b
{
5 x- t' S2 c9 P" U6 N! U8 l5 k; W0 k4 mprintf("Graphics error: %s\n", grapherrormsg(errorcode)); ) b3 R. a- q9 m7 h3 z
printf("Press any key to halt:");
. u& X* Z; D$ P0 l. C8 Sgetch();
6 r( S( { N4 \& v0 a8 D9 |9 Aexit(1); /* terminate with an error code */
) k, c$ l# T j/ V} 
$ X% d# R# m; e% @* N: K5 I) g. x( F/* draw a line */
7 W9 A0 {, e- Qline(0, 0, getmaxx(), getmaxy()); ) p& y$ _( X6 | k2 W0 w
/* clean up */
0 e# P( Q K0 n# M5 k, x& |1 tgetch(); & E: o0 q0 N. f8 _0 a2 Z; b( N
closegraph(); * U3 ^$ @3 B: S( _0 x
return 0;
. C: p0 c/ U4 n* e: _- j' n}
- a5 I5 o _+ r- ~$ s) Z& o
- E9 b a: Z+ r# Q
' @ R+ J( W" D" l& T2 ~函数名: remove 
 A6 s9 |$ t7 P0 t) @5 V) Y- H- a功能: 删除一个文件 ' j" i; M2 I" \# k
用法: int remove(char *filename); 9 Z. h6 v2 k( ~# d4 R
程序例: / @9 y2 ~1 W- w+ E* |+ ?4 U
#include <STDIO.H>$ \7 O; x1 z; E% y% I
int main(void)
# A: @: ?6 N! b8 Q# e{ 3 q$ E) t) P* M! `5 c
char file[80]; 
0 A& }( R* L) ~: T/* prompt for file name to delete */ : `3 p" M) s7 t
printf("File to delete: ");
3 ^8 b. t# u0 k( ]; d9 l8 mgets(file); % v' R3 A- ]$ w# J
/* delete the file */
& M3 \5 E; T1 R/ Q6 h+ c# sif (remove(file) == 0) 5 Q' P5 O, Y/ b
printf("Removed %s.\n",file);
0 O# ^- C3 E# W+ }else
; U/ e5 z$ ]" g/ ~1 h3 T8 r* vperror("remove"); 7 g- z; e; a; A5 r8 Z( ]6 B
return 0; / s; @# X; [6 Y+ M
}
. @ X$ Z9 ^) G: ^
3 D: K6 W0 f S3 {$ E- ]1 D" b) ^: t$ P
函数名: rename O( a5 Q0 q) N- W
功能: 重命名文件 " h& s% x& I2 o# e( G9 v; N* h
用法: int rename(char *oldname, char *newname); - Z: l* m' P$ R8 j% }" V0 Y- z
程序例: 
9 B. Q( h" a* ~2 |#include <STDIO.H>4 Y: X' r% O: o) O4 I6 s
int main(void)
 q2 x/ j. O. W0 g6 T" j7 ]{ ' d6 y6 _# f; j8 p% O% v
char oldname[80], newname[80]; 9 U6 I+ o6 K) o! P: ^0 u
/* prompt for file to rename and new name */ 5 B) |" s5 U8 Q$ ~! U+ D" w
printf("File to rename: ");
% k) L: i! Y3 Q) Y- _2 Ugets(oldname); " a* C4 _: R& C: A) ]( \0 c" p
printf("New name: ");
! L6 S/ D% }4 F# C* Sgets(newname); & y# @1 ?- ~4 U6 j& d
/* Rename the file */ + X% F. q8 b( Q* ^: n- c1 J k5 j
if (rename(oldname, newname) == 0) ; x; A E7 ^2 v0 ^6 t9 \$ h# V
printf("Renamed %s to %s.\n", oldname, newname); 5 E( c4 ]4 K! C3 R( o: H
else
& C; ^: `; D( sperror("rename"); 
( [% A Y! i, T! v5 W& R0 Ereturn 0; 0 `/ I* J: d3 u! ^5 C8 Q6 d
}
3 `) H& }. \! k; p% S y f* L0 {3 M, E: [+ P, q$ A

+ k' P/ S: @: H& Y! `函数名: restorecrtmode / `/ T0 Q. K* n: d) A/ m
功能: 将屏幕模式恢复为先前的imitgraph设置 ' Z) q& x( M8 k0 c. O' b! A! u5 G/ y
用法: void far restorecrtmode(void);
9 X2 {: i8 f1 P6 `# z5 {0 A- l程序例: # ?" X a. X/ @$ k5 [
#include <GRAPHICS.H>
: s4 ~% }" k) B- Q) F% H#include <STDLIB.H>) [: p* i ^, b( ?' N6 `
#include <STDIO.H>' ^$ n# |( |% R8 @% R' G8 N
#include <CONIO.H>7 h* O0 ]( r) ?/ V5 p2 p7 o
int main(void)
: N0 O0 I" ` ^% l' D ~, j{
& t4 s+ K b1 X9 r; ~: d% A/* request auto detection */
, d* |- `% b0 f1 {, uint gdriver = DETECT, gmode, errorcode;
3 R& z. }& x+ S3 ` Tint x, y; % m: U' g$ [( g1 K% a! u) e
/* initialize graphics and local variables */
# v% e# W& ~8 Q! J$ y3 ^initgraph(&gdriver, &gmode, ""); 
% c: t( H* b- L Y, I0 }1 Z0 _/* read result of initialization */
. `9 v8 p4 [" t, u- Z. Y8 _$ ]/ |7 @errorcode = graphresult();
0 c2 h* t" W" I) Q5 p6 u- vif (errorcode != grOk) /* an error occurred */ 6 s1 ]. a4 a j/ n$ D
{
8 K6 ^) _+ o1 }printf("Graphics error: %s\n", grapherrormsg(errorcode)); 9 d. p* q: Z6 `
printf("Press any key to halt:"); / D9 W' f ~( H5 l( V _
getch();
$ Y' A0 @) G8 B* I" |+ _, O6 `2 P$ yexit(1); /* terminate with an error code */
8 C" H3 [( y2 i& a3 `/ S} 
; q* `( o5 M" T* D qx = getmaxx() / 2; : n; ~3 q( }9 F) e0 {
y = getmaxy() / 2; 
7 {$ q! X( k0 J: h5 b7 K. O% P/* output a message */
$ j- b/ b: a+ m! s; d7 I3 ksettextjustify(CENTER_TEXT, CENTER_TEXT); 7 m) T% ~6 f9 L0 {& s" s' `# H
outtextxy(x, y, "Press any key to exit graphics:"); ; u% f5 e+ ~" r# J+ w7 [& f
getch(); 6 _, A! h9 z; ~
/* restore system to text mode */ * Y9 ] n z: F# b
restorecrtmode();
3 q8 X! } u* `( G+ p5 k9 ~printf("We're now in text mode.\n");
& b/ b2 g" I ?. z3 kprintf("Press any key to return to graphics mode:");
: c0 ` Z& ^7 [8 i( ^7 Q! rgetch(); 
% M0 y0 y3 [' H: ]; C/* return to graphics mode */ 0 Q' s5 p' R8 H: G/ e- O; t/ H- ~
setgraphmode(getgraphmode()); 
/ ?1 j, T- o) x* V t) x8 Z! N/* output a message */ 9 S. T# Y5 d1 T. l
settextjustify(CENTER_TEXT, CENTER_TEXT); 9 y/ f+ I1 b) J$ b- \. O
outtextxy(x, y, "We're back in graphics mode.");
2 l0 @4 x" H( [! c# J, y3 Qouttextxy(x, y+textheight("W"), "Press any key to halt:"); * v z6 o& V6 X
/* clean up */ 8 x; @) K5 _9 {- |! F1 G/ O8 U
getch();
* e2 t- T6 T/ u+ E+ E/ r2 h" C1 Xclosegraph(); - ^$ n# L# I8 f. B
return 0; 8 X+ `5 Q# K1 M* Z+ P8 `
} 9 Z1 J3 \. ]7 u# ~

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函数名: rewind 
( P6 C, I: D8 n; [& ~1 C0 I, q' |功能: 将文件指针重新指向一个流的开头 ( x0 S2 w, `7 X% E5 z/ c
用法: int rewind(FILE *stream);
8 w5 ? C6 {6 k/ c$ r0 F/ G程序例: 
% L9 g, G0 U' I2 J# B5 C#include <STDIO.H>
( ]6 P: i e! e' q#include <DIR.H>; p7 o) {5 Y' l0 D; m6 S' O5 [/ Q
int main(void)
, m( j' m) r/ {# R% E* F( Y, N{
# ~- w3 T. Q' N# e% ]" G+ hFILE *fp;
# K" ^: R, H8 q3 P' Gchar *fname = "TXXXXXX", *newname, first; & R$ T7 U3 M8 @* X
newname = mktemp(fname);
* W3 P7 ?# @8 x `, lfp = fopen(newname,"w+");
2 c# g8 I [ u' W# |fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
 W, h+ ?* h4 m! prewind(fp);
! y+ K7 ?" K+ L$ w! @1 K# l. yfscanf(fp,"%c",&first); $ X# F% h; E! A2 N
printf("The first character is: %c\n",first);
( a: ]& m8 C$ H* t `fclose(fp);
2 o$ B- ~( y: E% |! u' m- Mremove(newname); 
2 C4 _, R1 I- y$ g6 h: F; ereturn 0;
) X' v: E' b& @; `) ^/ l% n}
4 c2 X) a7 \; H. z" T! K# |1 I5 E' {# `8 J/ g( r

, [% ?; V. f9 I; g函数名: rmdir 
( i3 }9 J! J9 g1 e, b功能: 删除DOS文件目录
$ |4 y1 e: k! l- S: R( a/ M$ Y2 S用法: int rmdir(char *stream); & r. k- V x4 h/ U6 j) ]* H
程序例: & ~8 i# X6 P1 `1 G
#include <STDIO.H>
* p' G7 |8 p4 a3 s9 t#include <CONIO.H>
8 h5 f1 x3 `5 N0 |9 X#include <PROCESS.H>
$ B4 S: l1 P, b* G; X" @: B8 F#include <DIR.H>0 d# O" j, ]1 X; l, P$ j+ @$ {
#define DIRNAME "testdir.$$$" 
* \+ ]! y4 T# ~! M! d3 V& Y& t% }int main(void)
; r# P( S6 X5 c& J u{ . G& h/ T5 `, q$ ~+ T6 z8 h( h) F
int stat; + k. h0 |, _( E1 ]# E% f
stat = mkdir(DIRNAME); 1 t' Z3 a! y# ?* d
if (!stat)
; a$ y2 n. L6 g$ R# Gprintf("Directory created\n"); 9 N9 o; x8 R; L0 x% e
else ' t( R; f. z' \/ E* b+ J/ T9 {
{ $ ]. ~; A1 q# q0 v2 T* m( }
printf("Unable to create directory\n");
; ]8 g" j, P J$ U$ x mexit(1); # i- J0 w" _8 n; F
} 
3 t; E* K8 }2 |9 w5 g. y; v/ h( jgetch();
3 S7 s0 R" [! \) L9 p/ Lsystem("dir/p"); 1 f7 L( H$ i Q7 z; b7 m4 t
getch(); 
8 r& S- |: S& Y; ^$ ^' Gstat = rmdir(DIRNAME);
5 G5 R5 m! I' c, rif (!stat)
" h, T( _6 A, a4 |printf("\nDirectory deleted\n"); 0 l5 O1 U& U# Y l- X9 j' D
else $ j8 d' u: G' c7 x
{ + Y6 N) p, ]! K) z
perror("\nUnable to delete directory\n"); 4 ~/ T' W: U# I% R' u
exit(1); ! j' L' o# I3 f* X7 L* ]
} Y G Y% O/ l# x9 m' L4 M
return 0; - r6 k; R1 W. p( z0 q
}