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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); # [) ^+ Y, p- C$ M5 k: }
/* restore previous dta */
 u; C" Y6 Y2 r$ osetdta(save_dta); 
. b7 u: R/ H# A$ N/ [" Jreturn 0; 0 y! C6 S6 w( m: e5 A2 }/ d) t) U
} 
7 @! l8 V+ l+ L8 A9 N/ q3 [
" s! r! {, E' O/ z函数名: randbwr ' x& H+ C/ P0 o, v
功能: 随机块写 # v' Z; Q! ]0 e9 h
用法: int randbwr(struct fcp *fcbptr, int reccnt); 0 C6 v, E) Y( S& t6 r0 `
程序例: 8 y, c- r/ R7 ?. U% z1 @
#include <PROCESS.H>
* _6 U) T8 Q1 Z" V4 c#include <STRING.H>
* j. Q2 R5 I& ^3 L#include <STDIO.H>$ e; V; n) [( E0 n+ h
#include <DOS.H>; Q1 }& L3 { X+ u% m; S, Y4 x
int main(void)
. @ J3 O- O+ P( p \5 P4 \! b{
' `& r/ G% W# b) O0 schar far *save_dta; 7 j" w, A4 V- S# x
char line[80];
' }, P( u; A% Y7 @4 [# T8 G! xchar buffer[256] = "RANDBWR test!";
; n5 \8 B. g* r8 Fstruct fcb blk;
; `/ f K& y8 x( u; [5 Lint result; 
" v2 p, Q/ k5 E) n4 P% q/ A7 K( |/* get new file name from user */ & P% Q6 h& H. I% R; T* }" q
printf("Enter a file name to create (no path - ie. a:file.dat\n"); 9 N0 g$ `. p' B- _, u+ W
gets(line); ' K5 q% ?( n- C$ ?! K3 W$ o- {
/* parse the new file name to the dta */
, t6 B% L3 d# R; n1 mparsfnm(line,&blk,1); , b2 S0 l4 z9 u; D1 i K( P
printf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
/ O1 \* x A+ w/* request DOS services to create file */
3 r9 Q# ]$ g+ J9 V( Qif (bdosptr(0x16, &blk, 0) == -1)
3 c, v6 p! D6 p! N8 z# M/ @, a{
8 \& g6 t r8 B8 q8 }, u+ jperror("Error creating file");
+ ]( n& o2 z h4 U2 v( W9 dexit(1); 9 |# l& z; w) a; c0 o/ H
} 
1 O& P1 O7 x6 p' G" G+ \+ S/* save old dta and set new dta */ , g8 D5 V9 l- J3 r
save_dta = getdta();
, K; w( t; b0 k* A7 B2 ysetdta(buffer); 4 N% I! J& C* \5 }! {0 M9 W7 F
/* write new records */
# I( ~5 @2 u* d# h8 O B. }blk.fcb_recsize = 256;
( ~( ~1 j: y1 b( A) b1 `" |8 eblk.fcb_random = 0L;
( P% L ^( X' `( s3 g' Kresult = randbwr(&blk, 1); 
9 J6 W5 t q9 f/ V7 iif (!result)
4 q0 K) b8 Q0 f2 K. I9 sprintf("Write OK\n"); % J, s: I! @. i$ ^6 y" C
else
2 j+ \6 \6 F6 M% j' Z% x{ / N( v/ H* n. E5 W$ m
perror("Disk error"); & L: F' m" j$ z' N) ?9 c; \, |7 s
exit(1);
( J* h$ F+ Z. b- O8 [7 D- t} 
! m w9 x* ?+ N. X$ O* o/* request DOS services to close the file */ - J. ~+ x4 M! C( L5 X& E# a, s
if (bdosptr(0x10, &blk, 0) == -1)
+ ^- d. G# b; @' e, R" Y/ s) P{ 0 @ V4 Y* K: p8 x# t0 g/ L" n+ U
perror("Error closing file"); & ~: _- A7 @5 s: ]/ c
exit(1); % c( t5 Q! e9 w6 _
} 7 z: h1 _7 t- \+ q5 d* l
/* reset the old dta */
/ q& P$ G% z6 U6 I% `+ r2 Csetdta(save_dta); ) F4 [% C) W* X/ k6 @( l0 u
return 0; + |* J- u# I8 U2 R: A) g! K
}
% D- G/ @" @' g: A9 C+ D1 T& }! g" m
& j! {' ?8 Y' s$ l
函数名: random 5 F: V/ ?0 s7 @6 ^# P
功能: 随机数发生器
4 M, w* p, A! D3 U! M用法: int random(int num);
# I- j4 k# U9 d; u( H" ?; C- Y程序例: 
0 _! q( y7 [& L4 U; H/ ^#include <STDLIB.H>/ k( S" f4 I4 K0 a3 ]4 _
#include <STDIO.H>
1 Z8 S* c- b) l( h0 J% V; ~1 h' U, o#include <TIME.H>! w& v5 w6 C' C, w
/* prints a random number in the range 0 to 99 */ 7 h* v" n* l+ v: X' [( O
int main(void)
. P/ ^/ `) J! N" \% u- Y$ X0 d4 N{
+ z4 j" z" `! y& z2 Frandomize(); & Y- I, W6 k$ x$ } F
printf("Random number in the 0-99 range: %d\n", random (100));
, R0 D% w0 j# C% @* hreturn 0; " ~ V, e9 d+ B3 A' j6 H( B
}
/ p4 Q# O5 a# G. b+ I0 v3 O0 D- |) G4 ^+ W( B0 X d0 o

0 F3 m2 V% q, k& m* J8 M/ B函数名: randomize ! t4 v: U$ z1 A& K t# v
功能: 初始化随机数发生器
% |+ [6 c2 n' y$ {" @) ^用法: void randomize(void);
9 _" C' t2 {4 n8 H2 |, L: a# p0 n程序例: 
. K' I. r0 D. n) C+ }#include <STDLIB.H>4 m1 y& @- ]: p5 |& J
#include <STDIO.H>
5 }- u% i3 Z2 `* F0 e#include <TIME.H> v; O/ S8 }1 }5 `" D7 y
int main(void) ' I# j0 K2 W( {. S( o% a0 `' f h
{ # h" V. I" e) K4 k9 E
int i; 
7 i" Z' y$ @+ h ]( V" p8 krandomize(); # `5 |! B% `# ?+ n# P8 G, p
printf("Ten random numbers from 0 to 99\n\n");
6 n e) w. \6 e8 t! U' `7 ~/ Dfor(i=0; i<10; i++) 8 f0 c. M2 m# F+ p4 x" ?
printf("%d\n", rand() % 100);
; w# }/ x1 V! ]) d' W. ^return 0;
. ~) X: C# e3 M/ l# T} 1 b0 z% E! G" z0 B' Z

- _0 |- u7 m- _! w: J7 S7 d- p3 p, e! E
函数名: read 
. @; S$ \: }# K6 W功能: 从文件中读 ) m8 y! H" t5 P; O3 A" i
用法: int read(int handle, void *buf, int nbyte); : ]+ Y' h4 u- a
程序例: 
! |) P& d" V, K, q/ y& e" M#include <STDIO.H>
4 q9 x4 d9 Q0 S7 p8 L+ T! Y4 z#include <IO.H>
, D. {1 D9 N/ C4 x3 P#include <ALLOC.H>
7 c! Z T5 F0 O0 F# x#include <FCNTL.H>
' g$ v% \" j, E% b* {9 u- G J3 f#include <PROCESS.H>( O8 T$ ^. M+ R5 O, ^& l
#include <SYS\STAT.H> \. H2 X' J+ K) e7 `( \
int main(void)
; X8 a( C% ~1 i- T9 {& I W{ 4 x/ \/ Y3 l; I0 ?
void *buf;
5 g* ~- ]7 V% Y& Wint handle, bytes; 2 @9 V# G S7 l2 x3 o* W* k, d- i
buf = malloc(10); . S2 ^( V7 H2 _ r
/* : T; F3 ]! F" h) [# v
Looks for a file in the current directory named TEST.$$$ and attempts
3 G% U. b% R5 R! G- F* \to read 10 bytes from it. To use this example you should create the 3 }! D- ?, H0 t
file TEST.$$$
7 w9 d' `* ~- _. c1 H& F# q*/
+ j$ d2 w F' s8 A$ V& mif ((handle = & t2 \+ u! f( I
open("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1) 9 j4 G8 G5 [3 s, f+ K6 x S2 a. i
{ ' j8 h& z f9 [+ c- R7 X% n# D& E
printf("Error Opening File\n");
, {$ |% E) r% X2 B' Aexit(1); % m# ? B/ J7 K8 S5 T5 ?
} 
0 M$ C0 |3 _* D* x$ k0 ^' a1 u, Jif ((bytes = read(handle, buf, 10)) == -1) {
+ J1 [2 _- l4 b1 H( P) x: Tprintf("Read Failed.\n"); & C5 ]0 m8 e) k. _. u* e( h
exit(1); 2 J2 g6 j, e+ y- y, E( t# E
}
0 e) w$ z! c: ~" V2 F$ Gelse {
6 m- X, N$ S: b' l1 l, yprintf("Read: %d bytes read.\n", bytes); / ^% U& Z7 D% P- m2 h
} 4 r1 r. s: N# {+ N' d6 Y
return 0; " H- h$ t" p" Y+ l
} 
$ i. O8 ^+ C( |9 ~+ U+ q" |% `9 N# L# W4 d& e F! ]
5 r+ U2 S. R A7 T& _' G4 D# P
函数名: realloc 
) n5 |9 a9 Q4 z功能: 重新分配主存 , l$ R7 x# h4 s8 }% p! |
用法: void *realloc(void *ptr, unsigned newsize); * u$ H" G2 ~6 S( A# F: p
程序例: 
, `/ n) |+ j9 r1 o, Z* A! t/ a. M#include <STDIO.H>
5 b7 S6 R/ F# S2 }#include <ALLOC.H>
% p' M: H/ H4 d#include <STRING.H>
5 q) Z% V0 s) H, z5 V& X0 }int main(void) % X. J! _( M( E# W- Q0 P
{ 1 c4 X! B# R" z, K) @' S/ S
char *str; 
& x8 ~. D: ^+ S; X) C/* allocate memory for string */ . c7 h+ }+ j3 Q2 A' \, F
str = malloc(10); 1 e& t) H e+ N; }
/* copy "Hello" into string */ # L# i; K8 k8 r1 H, U$ N! `
strcpy(str, "Hello"); / p6 H/ o, m5 q: Z& N z
printf("String is %s\n Address is %p\n", str, str);
, T" P" I5 G$ a* B a( ustr = realloc(str, 20);
9 e% G+ L A/ K/ ?6 Mprintf("String is %s\n New address is %p\n", str, str); $ F4 a! t+ c% w' B1 o1 |- y2 \2 _
/* free memory */ 5 Z) ]! x3 p: Q5 m: Y) ^
free(str); ! {9 W9 a; U! \& t- q( O" g
return 0; / b/ B6 N3 q$ {; D+ H
} 5 u# K% n b# z( Z

' J$ ?, X7 n7 Y* J3 \6 x% G: X( J2 V9 y) c
函数名: rectangle ' f m, |& o3 c: g) [- c
功能: 画一个矩形 6 l. h5 @# o- { o
用法: void far rectangle(int left, int top, int right, int bottom); 7 S4 p5 b: }7 w7 H! u5 L3 k
程序例: $ I, M8 U( n- A2 V4 d& C% f- ?
#include <GRAPHICS.H>& D) ^. I% ] {+ k
#include <STDLIB.H>8 X' G! W; H" m3 A) G: n: o4 [
#include <STDIO.H>
" R9 x3 N5 H: |" G* p#include <CONIO.H>
: E- ]' S9 l4 q, Z+ Yint main(void) + f* z# d% q5 P+ I& ]. d& @
{ ' ]& L9 b' i; y' L* o
/* request auto detection */
/ a2 X Q! h' ~6 J2 t3 yint gdriver = DETECT, gmode, errorcode; " O: g8 m% N2 f) N/ _, l! h# K8 H0 p0 u
int left, top, right, bottom; 
 u: T$ D: Q/ D' K. e( p: W( T/* initialize graphics and local variables */ + A1 ~4 m. }% S+ d
initgraph(&gdriver, &gmode, ""); ; x9 Q9 b- b" s' [/ x# O, i' e& L
/* read result of initialization */
# k2 ]/ v6 Q% w5 serrorcode = graphresult();
9 U, O. @' i3 B# p1 Bif (errorcode != grOk) /* an error occurred */ 7 e: W$ w3 b' K
{ / x7 P7 J, d4 s9 z7 C! o% Z
printf("Graphics error: %s\n", grapherrormsg(errorcode)); ^+ l. E) q3 ?# N' N7 B0 R
printf("Press any key to halt:"); . e& k3 }' `/ W0 `- u6 w
getch();
3 X* `: E% E/ pexit(1); /* terminate with an error code */
) I& U3 S4 }/ W$ t( B} 2 E. }* ?/ y: F i. [) u$ L1 E
left = getmaxx() / 2 - 50;
% U" B6 u+ d+ {+ Z* y9 Jtop = getmaxy() / 2 - 50; H$ J7 W, N8 q: P# W: e
right = getmaxx() / 2 + 50;
/ j. }/ u" R* ebottom = getmaxy() / 2 + 50; 
& `9 n& Q# h* m; c+ p/* draw a rectangle */ ' \! c: F$ m0 S( H# r
rectangle(left,top,right,bottom); 
& _7 Q5 Z; d2 d/* clean up */
" z- h6 W$ T; _ K* R# g& zgetch();
' t. A9 \# x, oclosegraph();
: j& R* b: T) y2 K4 W, L; treturn 0;
3 }9 H: g. z! i$ y0 |& D& L} 7 B- V8 F8 \* ^% R9 w: g$ b! B

3 G* o1 Z7 H- C) w
& i- r/ Y) i: e' D; g8 Y0 O函数名: registerbgidriver 
, x, c0 x+ h+ G* p) l# ^& C& ?功能: 登录已连接进来的图形驱动程序代码
2 D; e7 B4 q6 e2 o用法: int registerbgidriver(void(*driver)(void)); " S% y6 j" K7 k% |1 p
程序例: & h3 M4 F& t }% J
#include <GRAPHICS.H>& a% ]; l- D! {- f1 _
#include <STDLIB.H>0 K2 R( G- K: w. ]/ T3 b+ l5 |
#include <STDIO.H>
$ J3 d$ `! ]' }: W#include <CONIO.H>5 Y1 p; U5 Q( s) f( ~
int main(void) 7 T2 ~6 ?; ~0 ]9 D- P
{
" I; s. y2 L1 [+ ~/* request auto detection */
" ^2 c3 K# A" y- _int gdriver = DETECT, gmode, errorcode; # I! B( j5 I" ^( O7 o+ K( M
/* register a driver that was added into graphics.lib */
+ y8 ]' y3 H. [% aerrorcode = registerbgidriver(EGAVGA_driver); 
7 M! m& t/ B9 e( C' o! A" F9 ]/* report any registration errors */
3 N/ ^( x. V( \7 s9 ]8 W1 zif (errorcode < 0)
0 O* M) ?" N+ A" q( s. f3 @6 }) Q{ 1 r m; d8 @! ~* Q. M* T
printf("Graphics error: %s\n", grapherrormsg(errorcode)); 5 a6 e& U& P: P2 O9 \/ g
printf("Press any key to halt:"); 8 i$ t! A' J# U0 g a
getch(); 1 `! m5 ?' S# ]+ R7 U+ Y
exit(1); /* terminate with an error code */
( O! Y) @8 s- Y2 X- W0 r) t% ]} 
/ P! o6 P- S- P* @2 _/* initialize graphics and local variables */
. ~) N% L8 C6 q K8 U* u) a, |. h% Ginitgraph(&gdriver, &gmode, ""); 0 I8 d( e/ k3 r- d: V# h
/* read result of initialization */
7 a$ `) |- I) N C* m) \2 eerrorcode = graphresult(); 8 [+ n- Q2 g* W8 g
if (errorcode != grOk) /* an error occurred */
# J5 \' s: ^' O7 K P' _) {; K{ + Y7 C0 ]) Q* S/ a
printf("Graphics error: %s\n", grapherrormsg(errorcode)); * X9 v- H5 C3 I
printf("Press any key to halt:"); - p% Q, r$ n7 q* Z3 l5 z
getch();
2 n7 _ d/ k7 Xexit(1); /* terminate with an error code */
5 {5 s2 O* g1 v; }7 Q. H} 
9 H! b" N8 E# M) e1 q- A. I/* draw a line */ ; \+ B- i- f/ K( d
line(0, 0, getmaxx(), getmaxy()); , C7 h0 K. h. z% I9 z( r
/* clean up */ & V$ N" `, ^7 x. A6 f2 Q1 Q7 r+ k
getch();
$ W$ B0 n" Q% R6 d6 S% e, Dclosegraph();
/ G8 Q5 ^' v" C Ireturn 0;
$ ^( y; n# |- p9 B5 f6 R- N}
5 ^5 u5 I! |" v/ S
( q# \& ~( x/ k0 w. ~, e8 H$ x0 D4 i8 r/ N, [ Q& f7 S
函数名: remove . j! S% u4 Q$ S7 u1 ]) z- ^8 _
功能: 删除一个文件
/ m5 n) F1 e& @0 d ]; ]用法: int remove(char *filename);
3 l1 ~- n% q' _6 T7 V* }4 c( \% v. Z程序例: 
6 O' p% s( x& Z+ h* c% ]& x#include <STDIO.H>4 ~7 z& b5 J. Z& h
int main(void) , E a/ U: q# [) O
{
! H: D0 ~/ b( _# x- Xchar file[80]; 
! V( O; g3 Z& t- P/* prompt for file name to delete */ : f4 R* [9 ^7 b& `' m8 r" r: }$ K
printf("File to delete: ");
& Z7 @& X# e7 Q) W& T% ]0 Hgets(file); ) P4 \* F$ {2 }3 e- k
/* delete the file */
* k1 j& q+ |; ~; u, l- |% wif (remove(file) == 0) 3 i: K' I& I& g; } _6 r
printf("Removed %s.\n",file); - Y4 x1 u O4 D3 v0 {& ^1 u" d
else ! a0 D8 P i0 P7 m0 b6 Z
perror("remove"); 
# [* Z: U" c/ E! V8 M2 Q4 Ireturn 0;
- c% O5 |0 N& Y& y; j} 8 A' j. c/ r1 k; f" p; i
( H) ?% O8 q9 n/ s& k
8 q6 `/ g& R K" M, T% S, m% O
函数名: rename 7 ^0 U g+ B0 [5 h8 n) A6 D `# Q
功能: 重命名文件 6 }7 j: h* z {6 Z+ _ Y; M
用法: int rename(char *oldname, char *newname); ) p& E+ F' o5 T: U, U) {7 ~; q) y7 l
程序例: $ M) x% `2 Q9 Y' j' N& R# v( [
#include <STDIO.H>
5 V. {; ?3 m: Q; O7 _# Vint main(void)
1 n! A3 e" X: k" f1 M{
$ A: q6 r) i* t# w* u1 zchar oldname[80], newname[80]; 
" j1 y9 W. Z: G* k/* prompt for file to rename and new name */
9 b) O* ?* ?% K, Qprintf("File to rename: "); % |) a' t& o* o# Q2 L
gets(oldname);
0 {) h8 M% q: [; mprintf("New name: "); 1 Z% n) T- Y, t) }- e8 ]
gets(newname); 
* p; }) I1 F) A( v/ [/ b+ o/* Rename the file */ & p& z1 X( l+ y1 b4 W; v
if (rename(oldname, newname) == 0)
, h5 C7 p6 P" q) Xprintf("Renamed %s to %s.\n", oldname, newname);
4 y) B1 V$ L8 g# V( melse 0 S. G) B$ y8 J% T% t5 d* m3 U" |
perror("rename"); % X3 J4 s9 B# L! g' h2 W
return 0;
; O, D& p2 {. w) R; J2 g8 g) I}
, M1 I+ I& Q. `0 B! t* {% M4 _' z0 d& q6 Y

" Y$ m7 @5 ]) [' m' S% p I函数名: restorecrtmode 9 y# q3 x3 {0 w- L |
功能: 将屏幕模式恢复为先前的imitgraph设置
' |" l* E; k5 W( X8 _用法: void far restorecrtmode(void);
; R& [- ]7 p/ p8 c程序例: 2 q1 F! X/ z. U
#include <GRAPHICS.H>0 F0 G" S* e3 @! K# [" P* b7 l4 e
#include <STDLIB.H>4 b& X g$ W( o1 a a8 ]
#include <STDIO.H>
% p. h( s) [3 B$ _3 r#include <CONIO.H>9 E7 E3 K! b# z( R3 c
int main(void) ) \$ k! P5 Q1 d4 D% k
{ ; Q; I, z& n/ }/ L
/* request auto detection */ * w+ f0 u D$ k) Y. f
int gdriver = DETECT, gmode, errorcode;
9 ?/ D- E- b: Z& r. j: c5 X4 M* hint x, y; " d4 h; U) V# b0 s7 I
/* initialize graphics and local variables */ ; W' V% Q8 i q$ t+ i, \: z
initgraph(&gdriver, &gmode, ""); 6 v- I( F% a& \+ V, n4 M: Y
/* read result of initialization */ 3 E' N, V6 C" x! I- n H
errorcode = graphresult(); . E1 c. ~) A+ V) C$ B
if (errorcode != grOk) /* an error occurred */
% l- t' D' e1 G# |' j4 w5 W. G{ / S& T% b0 ?1 ]. O9 k
printf("Graphics error: %s\n", grapherrormsg(errorcode)); 5 r- M% X, V' e+ V; c2 h1 K
printf("Press any key to halt:");
1 {! F* d( Q7 L( t0 |! @' Zgetch();
+ h6 y0 s$ G4 } Wexit(1); /* terminate with an error code */ ( y. f' Q/ G! [6 y
} 
0 w( l) {& ~" V/ E# D$ Jx = getmaxx() / 2; a( b9 v( M4 u/ L9 e
y = getmaxy() / 2; 
; f% t. R0 G* |& m0 l4 y/* output a message */
* U) @1 q6 u2 s" P6 Y3 I' }settextjustify(CENTER_TEXT, CENTER_TEXT); a9 {! \/ b! [5 t
outtextxy(x, y, "Press any key to exit graphics:"); 8 N+ T4 Y7 B. _+ c8 B8 a5 c$ X6 p! \
getch(); ( q+ l4 p) k/ E) f. Y7 w& a
/* restore system to text mode */ # L h0 j; s' o& k6 Z
restorecrtmode();
4 F8 o; A) ^0 Y! Pprintf("We're now in text mode.\n");
" b) k {% P2 |9 rprintf("Press any key to return to graphics mode:");
" f7 o3 J- Z+ `7 M7 Mgetch(); / L3 O: @( f- g4 n2 `
/* return to graphics mode */ . y$ W7 |+ Z& y, w
setgraphmode(getgraphmode()); + O7 ?2 X7 G& G, r) |8 v+ b
/* output a message */
$ p Q6 I1 c9 K% D& ]6 Y1 Zsettextjustify(CENTER_TEXT, CENTER_TEXT); / L# I9 B' w! D" p( M/ \' C
outtextxy(x, y, "We're back in graphics mode."); ) `; X) S% B' V) X7 I! N
outtextxy(x, y+textheight("W"), "Press any key to halt:"); + b% L- V& D% o( l% r7 k
/* clean up */
: S) A% O7 Y* s! E( p Ygetch(); ) Q- f3 \6 {& {& l' k) z
closegraph(); & M" W( T2 F' _
return 0;
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5 i g/ a( H1 M7 @5 j$ B" u函数名: rewind 
! R5 _( U- Q# k( p功能: 将文件指针重新指向一个流的开头 6 w0 |! s% G& N) L' a8 O
用法: int rewind(FILE *stream); / W! m$ M7 ]' A! K
程序例: 5 G4 H V8 e7 b
#include <STDIO.H>
 R( y& p% [1 `' I#include <DIR.H>
/ H3 @: E5 q/ T- \7 aint main(void)
) I' [, w6 @! {' v/ v- T/ `{
7 f) I$ A+ ^) y2 h! vFILE *fp;
2 p8 m9 D/ C0 J$ Echar *fname = "TXXXXXX", *newname, first; : T4 {) d- Q/ B& Y
newname = mktemp(fname);
# i; ?8 V. F# ` E3 R" ]8 }fp = fopen(newname,"w+");
6 j; P* t U6 b8 g' ?fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
1 _# E" J$ `" @8 x; D5 t urewind(fp);
+ t& T- j0 i' Q" @9 G% ~fscanf(fp,"%c",&first);
* A; m) q4 |* D3 Fprintf("The first character is: %c\n",first); ) |( G" }, M1 B, q" P4 Y7 b
fclose(fp);
/ r; u# f# m9 m" E* l3 k: v: Gremove(newname); 
8 P) j) l# r3 q( i# U% F. Hreturn 0; N* w: H- ^: ]! f! ~2 j
} & h9 ^/ B& C: Z. r
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/ h7 j0 v* F- O) O' w6 ?. X0 x函数名: rmdir ! T: H. p; L6 o- x1 n1 N5 r. q
功能: 删除DOS文件目录 : t" q, P0 ^- w! \0 m) a
用法: int rmdir(char *stream); 7 ] D: t4 s0 W( i% O; a) U9 l+ Z
程序例: 
8 X! N/ H8 F! S2 y. K; E#include <STDIO.H>9 p4 s- I. p$ E5 D& F4 R/ [
#include <CONIO.H>
' U; ?, c6 X6 x#include <PROCESS.H>
. p2 D; c& j8 n7 b+ k3 J" [#include <DIR.H>
4 x" A M- L) q+ p: p+ a" o. a#define DIRNAME "testdir.$$$" 
/ ~& o3 g5 v F8 K9 dint main(void)
% N: z2 H* @$ I" H. X2 c{
" J5 G) [4 i( P4 V! p' sint stat; 
1 H0 J2 W5 ], ^6 z% w5 Mstat = mkdir(DIRNAME);
$ P7 |$ {5 F1 [6 e% G4 @8 {if (!stat) + M& R( T" @$ f, d) d( f9 J6 S
printf("Directory created\n"); * E- J7 d* O0 J8 X$ ]4 i
else
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printf("Unable to create directory\n"); ( i* f1 I0 C4 f
exit(1); 5 t& U) I7 Y- ~" M0 H3 B4 c6 k
} 
( q9 W' p9 {, ~getch(); ( q' [7 e. J( n5 K* l0 g$ A. a
system("dir/p"); ! k: Q/ [) }8 f8 V# i
getch(); % d# |. R7 ^; d. D- f
stat = rmdir(DIRNAME);
/ \3 U4 {; W8 V+ V. Iif (!stat)
7 v) K- B" Z! Sprintf("\nDirectory deleted\n"); * W7 Z% a0 _* o: ^3 y
else ! F- n* e! \' f
{ * l9 c- o. y: }& z1 K! S$ p( a1 Q
perror("\nUnable to delete directory\n");
+ H% c9 b- \; ]( Wexit(1);
& u' r! K z0 n( a4 K5 k} 
, ]; p! F0 b2 I: N& {return 0;
- @( T% y2 g7 _}