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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); % e( ^0 _% A4 l) t8 }4 ^0 g
/* restore previous dta */
setdta(save_dta); 
 w, I1 P& u. [ rreturn 0;
* ?1 K$ n! M- I" ]3 G; F} , T; P! R0 t X4 i$ c3 L" i' Y! P
- Y5 c$ Z" h2 O3 U
函数名: randbwr 1 t" p9 a7 m$ d$ d# v
功能: 随机块写 4 O+ q, t: y: ~% [2 J) M& M
用法: int randbwr(struct fcp *fcbptr, int reccnt);
! K4 P. x4 \8 A3 y6 a程序例: 
 k, G( d4 H1 E, X+ R& T#include <PROCESS.H>4 j) ^% B& N- i: c; \ p2 t/ d
#include <STRING.H>
: d: |6 E* q# l6 X) C#include <STDIO.H>8 L( a Z# [1 Z6 N$ k
#include <DOS.H>& h% ?. h8 \: E& ^1 q
int main(void)
% a- m. N0 x2 j& `% h) f{ , t" `: i% \; |2 \ t; s) y, s
char far *save_dta;
0 i, @1 L! H- F9 mchar line[80];
3 Q- G: x9 L8 |3 l vchar buffer[256] = "RANDBWR test!"; ' ?4 N! W* A4 Y! L
struct fcb blk;
, [; c" |6 \* F' ~/ P( m0 `int result; 9 i4 v. a9 a' i0 N1 @- ]9 o; Y/ q
/* get new file name from user */ 9 v7 P5 L& I; I3 F+ R2 V$ N, I
printf("Enter a file name to create (no path - ie. a:file.dat\n");
9 x2 c1 d0 J, h0 J) \6 {gets(line); 
: P6 Q% y2 ^% O( r) {/* parse the new file name to the dta */ 7 A$ `3 @( n6 }+ D# w8 A" T3 _
parsfnm(line,&blk,1);
( J' B; F4 V: i! J# E2 kprintf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
/ n+ Y* I* O5 c- r6 \: [8 Z/* request DOS services to create file */
# I& Y9 Z9 e% D+ H9 E0 Wif (bdosptr(0x16, &blk, 0) == -1) 7 F- l5 D, Z/ y4 p* y
{
, `0 I3 p, H& b- F6 I, sperror("Error creating file"); R' v K0 v5 z3 T
exit(1); 8 |6 L. H; E" {# `& W8 q
} 
$ j# N* j- K L0 Q5 K, k# y/* save old dta and set new dta */ , @ F3 r6 Y( a& p( }& H
save_dta = getdta();
2 S* ^7 Z8 p- t F7 Ysetdta(buffer); $ i! a% T0 @" A7 x8 A( X8 J! y
/* write new records */
/ q7 M, l1 G" N, x( i* }blk.fcb_recsize = 256; $ D* e$ m, I# L" M! k+ U# u
blk.fcb_random = 0L; * @0 t- A" N$ J7 @& `* w
result = randbwr(&blk, 1); 
, ?7 q" ^: k! bif (!result)
* [0 \- V! T& F5 _! F0 jprintf("Write OK\n");
/ x( i( Q W$ ]8 Z1 Relse
$ L x5 M6 |4 T' D{
( [5 g/ @, _0 l1 F5 H7 dperror("Disk error"); ! @! [2 D# c- @# }
exit(1);
) } \. ^7 E1 j3 `# r! L( Q3 z} 5 \; O4 m8 y% X6 m& }9 v( f$ Q' Z
/* request DOS services to close the file */
1 A' m- n5 p3 C& eif (bdosptr(0x10, &blk, 0) == -1)
" g/ e1 ^) J R. q2 T{ 9 `, N. }4 |' L) |& {( m2 d
perror("Error closing file");
% [& |* q9 B4 oexit(1); " ?( S( ]) h4 O8 H
} 
3 A& I8 g; ~: t. o. \/* reset the old dta */ * V! R4 H3 X+ B9 `* `" D
setdta(save_dta); ! L# l( q+ I0 d9 M: i* s
return 0; 5 B; S$ {' M: T: J
}
# {- m# C! }5 M3 g
* K6 | r/ Y% l3 C1 N2 L- B) P% C) v/ w! M
函数名: random . d3 x1 P1 w, ^( {! F' H( [
功能: 随机数发生器
) |( t) \1 b8 c4 m用法: int random(int num); 3 I: Q! U; e0 ?, T* Z, O
程序例: : c3 _. B9 f6 {; V/ y- l. I, o
#include <STDLIB.H>
3 u2 ~- D- K% o9 K#include <STDIO.H>7 h( I7 m4 t1 c' x( c) b- w
#include <TIME.H>
 f/ c) G+ a4 T" C/* prints a random number in the range 0 to 99 */ 2 \8 k. r/ t9 P& Q2 E
int main(void)
0 g; f+ p E( K" H{
1 R7 k* D+ O/ B U8 F! Y$ Qrandomize();
 [1 j5 `/ ]: [1 c2 b( K0 D' \; Vprintf("Random number in the 0-99 range: %d\n", random (100)); , S0 z K" X: Y7 _- c
return 0;
4 t2 i& z& c) G$ b) Z, H}
; V" g$ F4 m! l# r4 e# j9 J9 c0 Y! p! C. a
& f0 [8 _ S; X1 y5 e, d6 P
函数名: randomize 
! C. s4 k3 u# E9 G功能: 初始化随机数发生器 % [- K/ _7 [) M3 f' [/ N6 S6 k
用法: void randomize(void);
( s0 [8 N0 ]" m程序例: - |6 ~3 U/ \" w5 S
#include <STDLIB.H>7 v: t0 `2 }- u, j9 D6 R4 A
#include <STDIO.H>8 D; T% c$ X+ ]/ R
#include <TIME.H>' e& e Z+ u2 d( W# f! M
int main(void) % B. q6 L) w1 C3 w5 ~0 |4 z( H* Q9 D
{
" J: b+ T% [- z5 \int i; ' K% H6 u1 `1 H; Z9 m8 E
randomize(); 6 c; W) y- O' W- T
printf("Ten random numbers from 0 to 99\n\n"); ; D( B0 v4 W0 ^4 B
for(i=0; i<10; i++)
6 n/ }8 J$ z" C: \% m1 }: r3 pprintf("%d\n", rand() % 100);
7 v$ t5 n2 @& e% H8 R6 ureturn 0;
, I/ n2 y+ B% B% C5 f: i% \}
6 J9 u; r7 ?& F' J0 V# {: e; M% q# D4 y( _

5 j4 a0 ~, P% }: [- u4 H: u函数名: read % I$ y3 A' C9 v, o: q
功能: 从文件中读 5 q* [; h2 V5 Z. s& s1 I
用法: int read(int handle, void *buf, int nbyte); # S" L" S* g9 Y6 I$ E# w
程序例: 
, j# Z! t* p3 K#include <STDIO.H>
& p. O* @$ {1 N: u: q8 r$ v- z#include <IO.H>
$ s* e/ ` f. b3 f' B7 }#include <ALLOC.H>
" E* ]( M8 @1 A6 @% }0 n, H3 N! X#include <FCNTL.H>
2 V! ?% Z# V1 P# b: V( _" y#include <PROCESS.H>6 \' P; l7 t: j# w
#include <SYS\STAT.H># A+ f* ]1 b5 W+ H8 w
int main(void)
4 C, y- O6 |! d5 p) M1 `# ^6 O% V{ / g1 O3 y! D5 }% `9 |
void *buf; ) V7 ~5 t* d& O" I5 N% H
int handle, bytes; 
% ^; e' l) s. q& F! [buf = malloc(10); 5 U- S* K$ H/ s- m7 Q9 | j7 P' ]
/* k5 C8 X( S# \- Z
Looks for a file in the current directory named TEST.$$$ and attempts + D7 f" l8 ]3 v _* P
to read 10 bytes from it. To use this example you should create the
 W9 F6 E5 s; K' V4 V8 _1 L9 W1 }file TEST.$$$
/ b: M2 j8 u* E4 m9 J*/ / V5 |2 W4 F# N: w6 v$ p
if ((handle =
& X, O- n, O. C; ~2 B' `open("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1) 7 j" Q$ p3 ]0 h2 t6 b* E' E7 ` k
{
% x, K: l3 d d+ }) j/ Qprintf("Error Opening File\n"); / g1 x" u4 W" j, _6 ^
exit(1);
( Z. ]7 ]' ]( P' e: O: w( Q1 [6 }} 9 L1 _5 S; a. r$ l6 G
if ((bytes = read(handle, buf, 10)) == -1) {
: n2 a" K6 `# p; iprintf("Read Failed.\n"); 0 p' q4 ?3 G3 S
exit(1);
" ^- W+ y8 A0 c, z}
; U4 r F3 p+ ?1 d" j6 N) D; Jelse {
; q( o% N+ r8 L' B4 i, T& Iprintf("Read: %d bytes read.\n", bytes);
" L6 T, j* q& X$ z# Y7 J( u}
5 w! H1 B3 i. ?5 ?return 0; / r! ?/ C0 c: N/ E
} 
+ C9 g" [6 @2 B' W& y
1 Q& V* u" O' I+ E, W9 ^
" N4 e7 n6 |& B# Y' Z函数名: realloc + i0 H9 f0 S2 L& v
功能: 重新分配主存 7 }6 H5 V! N3 ~
用法: void *realloc(void *ptr, unsigned newsize);
6 s9 E t) ~6 O8 U程序例: 6 ~4 I0 K" }4 Q
#include <STDIO.H>
. C; r; V( H( t4 v0 S#include <ALLOC.H>* t* H9 b1 S+ w2 z# g
#include <STRING.H>4 ]1 S" T# u1 U6 s4 B; n, k
int main(void) 9 I7 N) J5 J7 t, E
{ 0 ^% w& s+ s; D( I
char *str; * Z, A8 `2 `; o0 [
/* allocate memory for string */
+ s% c7 _1 p# c* L* ]3 B. S& fstr = malloc(10); # G! Z' m: v* [. P" s% c$ A
/* copy "Hello" into string */
1 z$ m7 n8 o2 J8 M$ ~$ Dstrcpy(str, "Hello"); 9 @4 e" L6 U& S" }" m
printf("String is %s\n Address is %p\n", str, str); ! E1 u( a7 w6 S& g" j0 F
str = realloc(str, 20);
) l0 B( ~) e3 eprintf("String is %s\n New address is %p\n", str, str); 2 s/ D: k5 B" a4 A8 }
/* free memory */ 0 k- T" G4 |4 o7 k
free(str); 5 R6 f s3 m I
return 0; ( z; g! H6 j( T' a; t
}
7 G9 ?1 W ~( O f5 N2 L. d" J% Z. S1 V+ H5 {

# X( C4 N- l J" O; g5 d7 j6 N函数名: rectangle # G' |; K2 {9 e- R- F
功能: 画一个矩形 ' Q! [8 |: J5 q' G% m! f4 F. o
用法: void far rectangle(int left, int top, int right, int bottom); ( e9 m+ T5 L2 a
程序例: 
( i3 f) p& @% Y/ c/ O% d# s! y" e+ L#include <GRAPHICS.H>& N: }- A2 z9 h5 U3 z
#include <STDLIB.H>
( ?1 F7 a" C4 [; S8 o, l( B2 N#include <STDIO.H>
3 h" Q8 t+ n2 w* I3 l' \- _; H#include <CONIO.H>
; I& R3 z' r4 w, M$ E( G. W6 A- y: vint main(void) ; z8 [1 E8 o0 `% v% \+ V& k
{
! u1 v5 E2 I5 e( o4 |! A9 A/* request auto detection */ $ e( ^8 K! p8 n2 o8 V
int gdriver = DETECT, gmode, errorcode; & Q+ K2 ~) _6 e) i- |1 j
int left, top, right, bottom; . B( v5 s/ c& h+ z( L
/* initialize graphics and local variables */ # `7 O# H* @2 K
initgraph(&gdriver, &gmode, ""); 
9 i: t6 u; V+ W9 g) h. Y8 e: e5 _% @/* read result of initialization */ 5 W5 Z" v. z' M X+ s
errorcode = graphresult();
: t; i3 j$ c Fif (errorcode != grOk) /* an error occurred */
& y+ j5 I9 i1 G7 i- Y& ^$ N{ ! G& u5 w+ U: s9 ~
printf("Graphics error: %s\n", grapherrormsg(errorcode)); 3 k0 ?( m* i2 l6 }
printf("Press any key to halt:");
/ Z; T j, G8 mgetch(); 4 Q O' N/ R4 n+ y8 Q
exit(1); /* terminate with an error code */
1 |$ Y7 U6 J- V6 q+ Q4 y} 
2 c: P, _, I% X6 M: `, t- w( jleft = getmaxx() / 2 - 50;
/ G( A9 f" p- ltop = getmaxy() / 2 - 50; / g/ j2 Z% C7 R; \( c! y
right = getmaxx() / 2 + 50; ( s4 M! v1 r7 V0 ?' B6 S
bottom = getmaxy() / 2 + 50; 
 n* [ `" ~" S# g' i& _$ Z/* draw a rectangle */
3 T( r1 N0 b! b: }. ~rectangle(left,top,right,bottom); $ @. {/ Q5 x" `( U M( M5 _* z V
/* clean up */
0 {" l4 G# h* E; z! [; P, Pgetch();
5 o( L; K# | z4 `- G) z+ G' Hclosegraph(); & \- i9 [$ L0 w6 f
return 0; ' D, _5 `# w4 m* Z7 Q) t
} - X+ y. M/ W5 P9 ?

" \9 |+ j J0 G3 T9 ^% r+ \# R4 N0 w. J5 @ _
函数名: registerbgidriver 3 g0 v2 T/ o4 b+ W/ q. W
功能: 登录已连接进来的图形驱动程序代码 / P; Q# W, ?% n8 D+ `4 T
用法: int registerbgidriver(void(*driver)(void)); 6 y8 B8 j' _: Y" E" o
程序例: - \' A2 d: [2 P9 O
#include <GRAPHICS.H>
8 k, [1 X( X$ H% n+ M" Z#include <STDLIB.H>' s6 F% R5 o7 B: |! ]. x
#include <STDIO.H>2 H% L/ W* {- d' c
#include <CONIO.H>8 G6 S/ ?7 _5 f# I' D: Z& I$ E; i
int main(void) 5 r' N$ C. t3 s
{
% P k4 g1 G; p# F/ r2 Q, \/* request auto detection */ 9 ?/ {5 H# v; Z4 s
int gdriver = DETECT, gmode, errorcode; 2 B; n/ G# E& j- @8 i) P
/* register a driver that was added into graphics.lib */ 8 X7 j8 i$ V7 j! j! ?
errorcode = registerbgidriver(EGAVGA_driver); . v! F3 i' w# L% ~4 X6 z& Z' J
/* report any registration errors */
! G, g: [" u0 i0 e5 R$ B( Xif (errorcode < 0) , ?* q m. T' V# ~
{ 4 h/ a, p( }8 I# K+ P. v
printf("Graphics error: %s\n", grapherrormsg(errorcode)); / s: |/ u# P0 Z% I5 M8 a
printf("Press any key to halt:"); 5 l. J# e3 n9 ]0 ], t9 Z
getch(); 4 y# A3 I5 J/ Q7 H$ a
exit(1); /* terminate with an error code */
2 x4 d' R. |; B} 0 q; a6 Y# G2 u5 `+ F0 M
/* initialize graphics and local variables */
+ i/ _. H; |3 x: @initgraph(&gdriver, &gmode, ""); ; o6 A7 l& c5 `% ?4 X
/* read result of initialization */
+ V- r& J2 W9 Werrorcode = graphresult();
% m+ N5 S7 x5 c+ q( T/ \" Pif (errorcode != grOk) /* an error occurred */
9 W& U4 Q( | f0 t6 O) t& j- x{
 i9 a' @$ ^+ l* l1 jprintf("Graphics error: %s\n", grapherrormsg(errorcode));
1 J" F/ \& F i5 C; C- A; Dprintf("Press any key to halt:");
6 m+ c' c. [% Wgetch(); 9 Y1 C- |; U5 k% V7 t3 J8 C; S
exit(1); /* terminate with an error code */ 8 V5 H9 p# E9 H: c) K" I
} 
$ T, h$ B8 r! g2 ^; n5 v2 ^, C8 B" ?/* draw a line */ 4 v, w, G3 I2 F2 H1 H' v* W7 K) O
line(0, 0, getmaxx(), getmaxy()); + J* ~, |+ v# Z
/* clean up */ & n+ h# j# f, e
getch(); 2 s1 R; d3 B3 f8 S/ s
closegraph();
7 r0 p7 D/ `9 \( J I- preturn 0;
" h5 \: e- S# S9 v7 d) f}
8 y# v9 O% k" Z! ?& l% ]7 X
) @& d, U1 s m9 E2 q2 L# @ T$ ^0 }( J o. K3 _
函数名: remove 
% p: h8 e; D7 V$ @; i功能: 删除一个文件 0 U( N8 a0 B X1 j D& Q
用法: int remove(char *filename);
" h ^' ^6 e* }" G! I, L7 [ ?! X程序例: 
" L5 z" ]5 h2 _3 k# l#include <STDIO.H>
" {! c: H" A7 E. x2 R0 g, kint main(void) & s* x! X: g: a3 G' x) E
{
char file[80]; 6 K& x+ L! {3 n4 t, F* B
/* prompt for file name to delete */
 P" S: q1 Y$ z+ Rprintf("File to delete: "); ' H; V9 k4 ^& f
gets(file); * F5 ?0 X) s2 y6 A
/* delete the file */ * x+ c( U9 e5 Z. f6 U9 c' w
if (remove(file) == 0) # b2 e$ P/ }3 w z/ A
printf("Removed %s.\n",file); ; x* u& ^3 |" \+ z$ O& { d
else ) ]8 e# |2 X0 }( E6 w- G
perror("remove"); 9 J; S* F: a6 Z' \4 U
return 0;
4 G* H$ ?/ j7 p( C) v; v- s} ! [: \: d( p" P
' r$ _: a0 x7 `& a- g- w4 d- @ j
: X4 p3 `/ C G
函数名: rename 
7 U1 J1 [' y9 m; x% Y' }; k7 M功能: 重命名文件 # j) \8 N2 a( t- F! E: b8 z" w4 m
用法: int rename(char *oldname, char *newname); - ]9 K$ S4 ? {4 o9 r4 i
程序例: % \4 M+ _: f( O
#include <STDIO.H>
, G; Q" h) {: bint main(void)
& v' l7 W: @' \9 u8 y% x' X9 Q! L{
. O7 C7 H( k+ b' tchar oldname[80], newname[80]; 
3 u* E) L# J( Y8 H# D) P- B3 P& t9 q/* prompt for file to rename and new name */ ) X' a2 F; _' j$ V3 _$ C! P
printf("File to rename: "); 7 `9 O- M7 u) @6 u( X% D% C
gets(oldname);
! K- \& D9 E# s2 J3 rprintf("New name: ");
; E" v/ }+ W" v. H9 {$ N- Dgets(newname); 
6 n' S/ s2 _! j/* Rename the file */ y% a5 [7 T9 z0 N) U7 ]
if (rename(oldname, newname) == 0)
0 O7 O1 e% M8 i1 E9 {printf("Renamed %s to %s.\n", oldname, newname); 9 X0 j/ j) Q, x: |$ n3 C
else
( v: q1 P/ ?9 r4 J3 }perror("rename"); 
2 j4 X0 y' z! C+ rreturn 0; ; F" Q/ Z$ u3 R1 }* j$ V( i1 @
}
7 t( c* e$ W9 ]1 p4 W9 {4 ]
% ^! X7 H! c8 M; P+ z% O4 g
- _6 p: w, X9 @% J) ^函数名: restorecrtmode 
' _2 s) d, [* M) V9 ~: ~+ Z0 A6 h功能: 将屏幕模式恢复为先前的imitgraph设置
2 R: P1 L' W3 ], w+ ]用法: void far restorecrtmode(void);
% s* J0 T- m4 V& V8 A程序例: 
- C N3 c' j5 O5 X0 M#include <GRAPHICS.H>, ^) }/ n! L& _5 w: b; X3 W
#include <STDLIB.H>
% z! b2 I' e' x: O#include <STDIO.H>. d8 m) t4 U G
#include <CONIO.H>) H# k6 |. e: O! G* C- ^
int main(void)
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/* request auto detection */ ' X6 W4 ^+ y _
int gdriver = DETECT, gmode, errorcode;
* t' M$ N8 h) z. ~; b/ qint x, y; 
4 o" { k" @! G- Q6 ?/* initialize graphics and local variables */
$ F/ ~* }0 ~5 H6 `6 tinitgraph(&gdriver, &gmode, ""); 
/ a, h4 `; O4 M2 j/* read result of initialization */ 0 S" ~ x* X9 r) |
errorcode = graphresult();
$ j9 |# `! l3 U% v, Yif (errorcode != grOk) /* an error occurred */
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/ ~, E( E' s$ C$ B- z/ B$ _printf("Graphics error: %s\n", grapherrormsg(errorcode));
4 o% D( b8 p/ w9 l8 aprintf("Press any key to halt:"); & b6 e/ c1 B! ?; h: l
getch(); 6 a& u/ ^$ l/ @( {; R1 |' W
exit(1); /* terminate with an error code */
# ~: W& X% s) W& }% \' D} 
% }( N8 D- a9 o9 M8 ex = getmaxx() / 2; ' ^+ ?- P! J, r$ E, v
y = getmaxy() / 2; 
( y, D! k1 x" A5 r i/* output a message */ $ F' k' E( ~& k) a% {# m
settextjustify(CENTER_TEXT, CENTER_TEXT);
0 e4 n% n7 b6 N1 f" [( v6 G7 ^ Wouttextxy(x, y, "Press any key to exit graphics:");
1 Q) F1 o# `0 n3 _+ G1 o! H fgetch(); . a" L1 {9 k7 J
/* restore system to text mode */ 9 J. Y9 _* d& {
restorecrtmode(); " @" \; g `+ w( Z7 z- P
printf("We're now in text mode.\n"); / m9 |% n0 o! n: b! D
printf("Press any key to return to graphics mode:");
) t. C! a* i' g6 \5 c7 Vgetch(); 
% r5 L- e; E! ^! e/* return to graphics mode */
 o: c5 B+ s5 m, q' S: D( Fsetgraphmode(getgraphmode()); 8 T6 Y2 T3 g( q0 H* \6 [5 @" e
/* output a message */ ! E8 O( {, W5 u2 ]4 V
settextjustify(CENTER_TEXT, CENTER_TEXT); ) W: J( e. K: [0 `9 U
outtextxy(x, y, "We're back in graphics mode."); / z! t( u( Q) {/ V
outtextxy(x, y+textheight("W"), "Press any key to halt:"); 
* R' E' \8 U9 R) b/* clean up */
% `# ~, x& o+ k- \6 `getch();
* c+ }0 T f( uclosegraph();
" k! t. q+ I8 X" mreturn 0; 9 y3 _ S/ _) n6 ~5 m, V. G
}
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 G0 M( D) o* l- J6 k4 Q: U7 {函数名: rewind 7 d' \. Z( @9 p# \, O5 N
功能: 将文件指针重新指向一个流的开头
6 d( H, s3 T8 q4 I; L/ J. k1 B用法: int rewind(FILE *stream);
1 U2 ^8 F* E( S$ K8 ?+ M0 u% K* d1 R程序例: 
% i0 o, ~8 e3 _7 A#include <STDIO.H>
/ {4 O3 V1 W& Y#include <DIR.H>
0 y. H# O) u$ p b8 a5 |% X8 Cint main(void)
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FILE *fp; " G+ b n; L1 E" ^4 f' a7 M. U
char *fname = "TXXXXXX", *newname, first; 
8 F8 U9 a: L, vnewname = mktemp(fname);
' Q7 q( c { p; nfp = fopen(newname,"w+"); . E0 y. V: O% y \# u& T
fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
3 Z- l& a: v1 frewind(fp); , y/ G% @- X" W
fscanf(fp,"%c",&first);
) w [5 q+ ?, Uprintf("The first character is: %c\n",first); 1 ^; P/ a I7 H0 h+ K
fclose(fp); # ~4 B8 N2 h7 X: {1 V$ o1 Z# S
remove(newname); 
; {& Y+ U2 ^! }+ `( e7 |1 n9 ^/ ~return 0; & I2 i. ~ A a2 d6 I$ ]: S
} 1 ?5 O4 f2 f+ t4 B" D
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$ j7 \2 J( V" j. j( d
函数名: rmdir 
' ]+ h, ]" ?; S# I% z. O3 o B功能: 删除DOS文件目录 : {. N9 D- z& J' e) X7 v5 Y; u& [
用法: int rmdir(char *stream); 1 f% i8 Z0 H9 M F0 M& m
程序例: 
( L" l! a8 k" ~- q/ o( _# @7 C4 [2 q#include <STDIO.H>( S/ K, W2 c5 v& b8 q! `
#include <CONIO.H>0 D6 C* s! l8 r) X
#include <PROCESS.H>
) [3 \! N( y% c. B8 @! L3 Z$ U. ]#include <DIR.H>
) y5 z/ ?% v8 @& U4 h, Q- W U% b" J#define DIRNAME "testdir.$$$" 0 N' ?8 E, U5 v5 `% L+ Q
int main(void) . G( }! w8 K: e6 a, [
{ - O9 R2 U7 R1 y! h, H* V5 c
int stat; 
6 g, V) I6 Y, R, h% i- E1 U$ ] Ostat = mkdir(DIRNAME); - |; F, I& j0 g* ]( G
if (!stat)
2 j7 n+ j4 ?/ u$ vprintf("Directory created\n"); 7 _+ K+ B$ z3 U, f; k
else
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printf("Unable to create directory\n");
! j- e8 X/ s% l. \% u6 dexit(1); ' B! A- y: `: m5 E" @
} 
6 B2 W3 u; `( y8 N* S& @getch();
/ t6 H: P( N+ \" a3 X) a( Xsystem("dir/p");
; x) N3 J* `( i. o* L) bgetch(); 
* d' w' e2 J$ x6 hstat = rmdir(DIRNAME);
7 i) w1 Z) v0 H" n* Lif (!stat)
8 m9 B8 I7 w8 k9 ^+ A& H; |2 J6 h) Qprintf("\nDirectory deleted\n"); 1 V3 ^/ V6 I- H5 G; ]
else " X v- d* J: Z* w$ d# O* k: J8 @
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perror("\nUnable to delete directory\n");
5 T; T$ E( C: S6 Fexit(1);
4 G! X, |5 m# k9 G} 
$ a% Z: { c$ n8 }, |return 0; : Q" Z* Z+ n! Q* }" \
}