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标题: 函数大全(q,r开头) [打印本页]

作者: 韩冰 时间: 2004-10-4 02:55
标题: 函数大全(q,r开头)
<

>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); 
 a. o1 `( L Y/* restore previous dta */ $ u& y, y2 n) y
setdta(save_dta); 
7 [ J7 A8 E0 E2 N1 o6 Zreturn 0;
! A* T# f/ }, G1 J} ( z) K& {4 I" m N6 p- t1 Q: ?
- d2 c9 w" }; n- Q/ n4 q. Y
函数名: randbwr 
9 {$ f% I4 Q1 v1 r) k功能: 随机块写 # b% x* W2 u ^- r" U4 J! J
用法: int randbwr(struct fcp *fcbptr, int reccnt);
: h$ z$ ^* i: H程序例: 0 k# N7 n! v8 p( f* k
#include <PROCESS.H>
* N1 Q( x* z+ k- c1 A7 h# K#include <STRING.H>
8 ]8 K; t5 L1 w% b% T8 U#include <STDIO.H>
2 f1 R; \* h4 l8 E% `#include <DOS.H>
; P: k' |; M/ y* [' [! j# mint main(void) n' w2 g. T+ R1 n
{
3 T) w" H$ o: o( c' l: bchar far *save_dta;
. F- D$ Z3 W) _1 x+ `char line[80]; * S- E0 f' ]0 L0 f, A3 I! F; d+ n/ C
char buffer[256] = "RANDBWR test!"; 4 [7 u1 ^: U) ^" s2 u5 I5 x$ A
struct fcb blk;
" q' t9 @' i9 g; j. g# d wint result; ( [' T5 z+ ]7 f, j- A; P {
/* get new file name from user */ ! `1 x; n* Z" f, c' D* Q. t
printf("Enter a file name to create (no path - ie. a:file.dat\n");
* t# o* W0 _$ N- Dgets(line); 
4 c7 z6 B- \7 i7 Y* f/* parse the new file name to the dta */
' @- p* v2 I( M9 m+ n. q2 J pparsfnm(line,&blk,1); " C3 \+ t: T2 `/ v* k* A
printf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
! r, y" _+ t$ i/* request DOS services to create file */ 7 Y) y$ l3 f Y. I' L7 j$ L" }
if (bdosptr(0x16, &blk, 0) == -1) ! @1 g! F$ W6 o# u
{ 1 q2 B$ |: b( I% q
perror("Error creating file"); % B6 C9 ^6 p7 n! w" K: }% U1 J& H6 F( J
exit(1);
" x+ C7 r J# o2 y4 c9 x} 
 Q* f* Q$ d4 Q* j, G/* save old dta and set new dta */ ! k Z$ f2 z/ t! E; T, C: ^( D1 @! s
save_dta = getdta(); ; y) a: |- E$ X" y7 s
setdta(buffer); ) M# X6 l6 X, R0 P0 `3 N
/* write new records */ % J. H$ l8 s9 R1 r
blk.fcb_recsize = 256;
4 s2 X# d n- _6 eblk.fcb_random = 0L; 1 d( W# m( V- p1 j; V
result = randbwr(&blk, 1); * \5 \8 A7 O* f% L" o1 Q- v
if (!result)
" \" r. q5 A" S. o3 Xprintf("Write OK\n"); ; k9 B+ Z/ v, Q
else
, ]5 J( ^6 _' y4 V{
, ~4 L- N8 x& Y; R Sperror("Disk error");
, i: g) |* {% ]9 P8 Q8 Hexit(1);
9 w/ a8 W& W% d: N( v- r" Z} {/ \- n0 w ^' _: l
/* request DOS services to close the file */ : O" K7 r+ T! H2 Q5 U/ d* t
if (bdosptr(0x10, &blk, 0) == -1) 4 n, h4 p. w2 m# I
{ ' q' g1 }8 o% b7 s+ Z( }8 U5 Q
perror("Error closing file"); # I P0 i. l4 `
exit(1); $ ? z& ?5 V+ A- |5 N
} i, ?- t6 [. _
/* reset the old dta */
. k. p, r D2 ~7 k& M& ?' bsetdta(save_dta); 
$ ?' Y5 y q& A+ Treturn 0;
, O' i6 M& S' }8 ?! C7 ?} * ]( o, A u: J( D, g1 [( q* J
! |! }& y& ^. H Z4 q8 ~! q- X
6 `# r! N2 G2 z1 J* e$ c
函数名: random - W6 j- a$ r+ Y/ r' r( ~) ^
功能: 随机数发生器
" U2 o5 D8 F# ^1 R$ v, h- O用法: int random(int num); - P% o% L% |0 K
程序例: 9 K0 z2 {' q8 f! g& `
#include <STDLIB.H>
& F5 {0 i7 r2 `+ c#include <STDIO.H>
' m! t! C9 r6 @3 A7 t: U1 H#include <TIME.H>
3 N: ]! ^1 F4 H( A/* prints a random number in the range 0 to 99 */
. s& L" |. Q. ]4 h: Mint main(void) # b/ g* X' q! {" t# K, y
{
( K8 U9 i: p( I& q9 }6 o9 h* drandomize();
: s" G, ], d& n! C3 Hprintf("Random number in the 0-99 range: %d\n", random (100));
% f" F; P+ \# z; d* jreturn 0; 2 }" N2 V3 F% I( J
}
* W# U( j& v9 h0 A; K+ A5 B9 p) N4 \* Y1 d: I5 U% U

7 r+ [2 u4 \% @% y- a# k4 u函数名: randomize 
: n2 N2 s( Q% u a& ~. N功能: 初始化随机数发生器 8 D9 {6 L: t& Y. y
用法: void randomize(void); 1 L+ C7 K2 t ~
程序例: , v" Y0 m; x( {( v5 B& g% Q7 j
#include <STDLIB.H>
. N9 z2 i4 z D6 L* ?#include <STDIO.H>
3 t0 p4 J8 r4 t* v4 ^#include <TIME.H>9 u* }: Z" Q8 F
int main(void) 1 D3 ?1 e1 M6 A- ~1 F1 k" F
{
) t; G8 @# \& \int i; 
- k, ?6 s0 {; b8 V+ Y( _randomize(); " V1 m- e1 w; p, w( g
printf("Ten random numbers from 0 to 99\n\n"); 4 m) n: d3 P6 B$ X, ?
for(i=0; i<10; i++)
# }6 G, H# S1 V; S+ Y/ g5 r6 Nprintf("%d\n", rand() % 100);
3 r; S% z! x: P0 S$ k# zreturn 0;
- x0 n) \9 m6 c}
 q% `) `0 {3 v( b. m9 q C1 q6 V3 j9 k! R

2 {! _3 P/ [% S$ x, L# S函数名: read 
- v7 Y8 f/ s1 R4 `- M4 Q; [5 M功能: 从文件中读
' w5 d. C2 y* V3 _& Z# d用法: int read(int handle, void *buf, int nbyte); 6 Q) @: @ y5 l; ?: q1 O
程序例: a4 g Z. D/ K3 K2 w5 K B3 y7 L) u
#include <STDIO.H>
% _2 \& L+ M/ z6 x( j4 p* S#include <IO.H>
& T4 o5 j( _' Q#include <ALLOC.H>
2 Y, V. T: O5 L7 x. k#include <FCNTL.H>$ f( r+ M$ e8 E ^ N5 {. c
#include <PROCESS.H>
9 D8 ]2 Z) _+ Z#include <SYS\STAT.H>% e& N& C: Y* |$ {7 k8 g
int main(void)
' s1 `& O# D( @{ 6 w; Z) D) ]" _6 }3 x1 q% B
void *buf; & `# E" ^: f# J
int handle, bytes; 
& S% A" ?; l) @% @" i/ h' k* @buf = malloc(10); V* @% _# d) ^4 p$ K
/*
0 H- g; ]. i' }" f2 W- y+ aLooks for a file in the current directory named TEST.$$$ and attempts $ q, q7 K# A C. @+ B$ a% s, E% [
to read 10 bytes from it. To use this example you should create the ! B. F7 c) o' @6 R; l1 E6 h4 M, D1 C6 j K
file TEST.$$$
+ J l4 c, r* J) z*/
( V2 f7 A- U8 g% Xif ((handle =
. @/ L$ P9 ~ k! Popen("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1)
2 z! N; Q/ ^, k- ?7 S" F: y{
 h& k# Y0 l; X* r1 W- E* gprintf("Error Opening File\n");
: r) _8 c6 C2 texit(1); * G; ?8 s+ Q: _' `$ B. O
} 
- s! Z2 g- e. E8 H' Nif ((bytes = read(handle, buf, 10)) == -1) {
6 x$ j6 K O, lprintf("Read Failed.\n"); 3 w; B; o1 W9 @" y
exit(1);
' a7 C2 G' e( F& e}
. _7 |& n# L6 o: x5 H' M# Jelse { 3 y4 Q6 n0 B" y- l' B& X) s
printf("Read: %d bytes read.\n", bytes); & q4 d" j( n+ T- E
}
/ Y, z% F' @; preturn 0;
& m) z, h8 s1 y% s4 R) W} , C6 R( D% N H' @! Y& a- [3 V: K
: z8 a) T6 o W! z& v2 a% R
8 u, Y, y" Z V; h1 q
函数名: realloc 
7 f! `' z3 l, {9 K功能: 重新分配主存
( ?+ v3 s6 {0 S用法: void *realloc(void *ptr, unsigned newsize);
 r+ q- x3 ?9 S程序例: 
1 O2 B4 X+ F2 q! a$ ^3 E* R#include <STDIO.H>
4 R0 U4 N, q# L v4 [#include <ALLOC.H>
8 l# f k% h- D#include <STRING.H>4 ?$ C' E) M8 s9 I" Q
int main(void)
0 t( `, y9 L! s0 h{ ( ?$ Q, S; i/ c& P: t4 j
char *str; 
* q/ N/ V# A# s( h2 L/* allocate memory for string */ ) I6 \& l# ~- m Q0 X5 l
str = malloc(10); " p& j5 R1 G/ {, G' |- H: K
/* copy "Hello" into string */
, I' N& g& P/ l& c5 mstrcpy(str, "Hello"); 
% d0 M$ A2 w. |# R |! B1 {printf("String is %s\n Address is %p\n", str, str); 7 y- Y( I( b' v. v! N
str = realloc(str, 20); 1 t/ R/ f; v2 f8 G
printf("String is %s\n New address is %p\n", str, str); + g! W; j+ E! A4 y
/* free memory */ " o% ]0 m5 t- K" J( u& N
free(str); 7 B0 ^5 ~2 A2 X1 F: W
return 0;
* J( c& r) G; f O} & T/ K/ _' [& b& l- W/ b0 Y e) ^
0 o2 u; @' g6 O# M
6 A5 ~- P+ B0 h) m1 h# Q
函数名: rectangle 
. t4 I# o# I7 v- q/ R8 m功能: 画一个矩形
5 Y, D, c0 W1 o: B0 [/ x! J用法: void far rectangle(int left, int top, int right, int bottom);
/ o& S1 Q! U$ q. w" G程序例: 4 c3 C6 ?8 f5 k. y# j8 p- c
#include <GRAPHICS.H>% H" j0 M& K6 | A X
#include <STDLIB.H>
6 x* i+ |; m0 t6 a#include <STDIO.H>
 w4 t) d5 O( ]. N#include <CONIO.H># w) o1 P/ C( T1 P/ r2 g* C
int main(void)
( M1 x- P2 Z; m( k{ % o! D# B5 ?$ i* `
/* request auto detection */
, h9 U8 t/ N/ \7 j/ Tint gdriver = DETECT, gmode, errorcode;
 }1 R) S6 R0 Wint left, top, right, bottom; , e3 j4 f! {" S) S5 f( B+ ]: w: s
/* initialize graphics and local variables */ 6 i/ O0 s; J9 u! @9 W3 ^
initgraph(&gdriver, &gmode, ""); 
+ S8 ~$ Q" r, A4 L; h$ ~+ [/ Y/* read result of initialization */ 5 h6 p) X- r; H$ \. D# U* |2 o4 S
errorcode = graphresult(); 1 E. @) y! r9 g2 v7 q. b& x
if (errorcode != grOk) /* an error occurred */
- `; T7 R/ y# m( R4 A5 o{ $ [) w8 _' I8 ^$ B- B& W" g. M
printf("Graphics error: %s\n", grapherrormsg(errorcode));
2 _) [% U: T4 q* {3 N9 Z5 eprintf("Press any key to halt:");
: |4 M9 a- G& g* Agetch();
1 U) I6 i4 v( e% r. l6 uexit(1); /* terminate with an error code */
9 y8 n1 B# K* g( a8 @} 
' @# b! T5 U* T6 o4 a" yleft = getmaxx() / 2 - 50; , ^8 |7 f# o$ n, s8 o$ ]' v7 y
top = getmaxy() / 2 - 50; 6 u) w5 c& B) k# v! A
right = getmaxx() / 2 + 50;
: h- b$ v' N9 S0 n# cbottom = getmaxy() / 2 + 50; 7 ]8 O7 P x0 y/ |4 Y
/* draw a rectangle */ 3 E3 A* z: @2 ~ y7 K
rectangle(left,top,right,bottom); % i4 _* T8 Z) V- D# b% o
/* clean up */ & C% D4 Q2 o' | V/ i
getch(); 9 k. ^& ], o* Z v5 G, Z
closegraph();
: | K( a! H+ N" }4 p7 r$ `return 0;
/ w i: u+ Z* ?# W}
) K# X/ F( U. i4 I. z/ a9 I$ b7 L' k# d9 ^( d8 q
) [" {0 l J5 J$ d( N& K0 G
函数名: registerbgidriver . R# E1 u) ^) }6 c* L% y7 ~
功能: 登录已连接进来的图形驱动程序代码
7 A( c& m8 L, }( g用法: int registerbgidriver(void(*driver)(void)); E& i9 W6 ^) `) g# s+ B
程序例: 
. B+ P* t, [4 A# y$ N$ J |#include <GRAPHICS.H>
 M" r. r( k9 I. G4 b#include <STDLIB.H>$ d2 m/ O1 J' y7 z9 k
#include <STDIO.H>
! |& T) N" o% C7 v1 _0 {#include <CONIO.H>& A7 {7 {+ z5 b$ T. l- Z
int main(void) ; Y$ J. y, ^% l8 R. v z- ?/ T
{ / p/ O Z6 E2 B8 S0 H' D* E
/* request auto detection */
1 b( H) j |! c( e) [int gdriver = DETECT, gmode, errorcode; * f* c: v9 @; P0 C0 ^
/* register a driver that was added into graphics.lib */
, v6 R5 J/ G9 @8 I8 ^errorcode = registerbgidriver(EGAVGA_driver); ! a v: k2 f* K* D9 b4 \" N
/* report any registration errors */ 8 ]: n2 J' m! [) ~3 V$ q! Q
if (errorcode < 0)
0 s ?: |* Z# v3 _' g; C& L{ - d9 e" R) i& }
printf("Graphics error: %s\n", grapherrormsg(errorcode));
% o* \ g, f3 N0 Hprintf("Press any key to halt:"); ) k0 j* `. u: M+ Q+ s3 u
getch(); 1 T% U6 x; G. j1 v# }! e
exit(1); /* terminate with an error code */
, ]/ u( y' O. X} 3 y6 P! j. I4 W
/* initialize graphics and local variables */ & \. |1 r: k/ k" b" ]( ?* r- k, q
initgraph(&gdriver, &gmode, ""); 
" L4 N! a& J( `" f% H' c8 |/ u/* read result of initialization */
! |, a# ?1 P0 K7 N6 s5 X! aerrorcode = graphresult(); " h) q4 {1 Y% m# N4 d7 Z
if (errorcode != grOk) /* an error occurred */ $ V y G2 A) B" c: W
{ 1 v' g1 X! X4 E. D; n; X
printf("Graphics error: %s\n", grapherrormsg(errorcode));
* K j, W- p& r6 Q" z1 f! n+ sprintf("Press any key to halt:");
3 E5 Q* [ [% Q3 {' rgetch();
8 L8 m- x% B+ K* Y; pexit(1); /* terminate with an error code */
$ ~0 Z3 I, p) [+ u, @} 
' X7 ^& e0 }2 ~1 x5 {+ f/* draw a line */ , c6 E5 J; z, G/ y5 z
line(0, 0, getmaxx(), getmaxy()); 
6 E# o& o ^. s2 c- Q/* clean up */
. I: S' \# I( b8 F. c2 Pgetch();
# p; I" s0 k8 Nclosegraph();
9 ^3 f, B# t3 Areturn 0;
% y7 U' B* r$ u- @! S+ j- \}
9 @9 `, ^( z3 u5 s( D, U! a0 y. B. _# A9 M+ h& d
) B& A# F" Q8 q0 X) ~
函数名: remove 
, h q6 n2 c2 l- [& r1 X- |. ~+ ^功能: 删除一个文件 " s) \: B" A) [7 ^: h
用法: int remove(char *filename);
' i; p/ U4 \( ~& S; P! F* |2 r; V, j程序例: 
2 @, l, G6 p# {$ N+ [& N#include <STDIO.H>
5 D% F- Q+ E! A3 M& lint main(void)
6 S$ P) I4 z) `( B }1 r{ ( w* H2 @: O$ z! h4 e
char file[80]; ( d$ T' X4 X! D- @ C; w7 P/ u6 w
/* prompt for file name to delete */
 I7 K ]3 j3 [# T) L5 Nprintf("File to delete: "); - e& m2 D, ?' T+ p
gets(file); 
+ G; G }& d0 m: b- b7 g* h/* delete the file */ $ t! O4 e- H+ Y
if (remove(file) == 0)
' b) Z5 |1 F4 G0 n/ f& G& {printf("Removed %s.\n",file); 5 h! o) k& Q6 m- \- Y% h
else 0 q& M. q' t/ T3 S. k
perror("remove"); 
# _/ E8 Z- ]) l8 j& F) D8 dreturn 0; # F W4 s( H# {
} 4 W3 s1 A1 ^" i4 F* e# X8 n

- a. x( Z7 n8 N& Z4 f3 Q
; ? I& ]$ H+ s3 S9 B函数名: rename 
( u/ d. ~4 t+ Z5 e8 R) V, @功能: 重命名文件 9 C: V6 H# x- k( Y
用法: int rename(char *oldname, char *newname);
7 i4 B2 f+ q( ?. w/ k) V' v2 f% r程序例: # O( f5 Q! b4 c( u$ Z
#include <STDIO.H>6 [7 L" j2 ]. y
int main(void)
& S( \9 i7 q- Y/ ~% d{ , T- _* e, V8 H8 d9 {1 R0 k. J
char oldname[80], newname[80]; / j: e$ @2 V3 V1 ~
/* prompt for file to rename and new name */ ( o- _9 f A& o" {" w
printf("File to rename: ");
( V( ?/ f' `7 J. b/ D& |gets(oldname);
+ l4 r! u6 ]( F: I! aprintf("New name: ");
. E& I( j# d+ K/ \2 jgets(newname); 7 J# {/ m9 F4 w2 J- d/ N
/* Rename the file */
: K6 E. z0 b$ Z c5 Zif (rename(oldname, newname) == 0) # ^8 y& _, K/ M. N" j) x5 P
printf("Renamed %s to %s.\n", oldname, newname);
6 @7 @; l. {7 u: n6 Jelse $ z7 Y9 Z$ [! o, o- j6 g
perror("rename"); 
& K% V7 u" R* A" S e! Q6 l* ~( Ireturn 0;
# l8 k) D9 Q8 w4 b/ ]" `7 U& |} . i3 w7 Y/ B4 R4 E9 Y
1 l Y, W2 [ m7 E

: J8 T4 _- ?0 n/ C' N9 p函数名: restorecrtmode " O% v0 A9 ^7 |3 E' b. g# D
功能: 将屏幕模式恢复为先前的imitgraph设置
 {2 @% F, E4 a( z2 N; p0 k- V用法: void far restorecrtmode(void); ; c* H3 e d, X
程序例: 
% a$ d, y6 X3 r0 z9 l#include <GRAPHICS.H>
9 w* ~. l ^! e. L#include <STDLIB.H>
3 C$ T/ @7 u, F, T#include <STDIO.H>
4 h" v# H' V; Q#include <CONIO.H>
- C0 p5 z3 @, V( r: b$ A$ Kint main(void)
; C; _2 A% d: S{ . u1 f8 `5 C+ ^: p+ F
/* request auto detection */ ) H1 k1 S4 M8 r x( U0 |4 f. G! p
int gdriver = DETECT, gmode, errorcode; 0 K/ [1 `" K( ~
int x, y; $ X9 A4 Z1 C: u9 @) @
/* initialize graphics and local variables */ 4 o2 K ^( c& Z5 R
initgraph(&gdriver, &gmode, ""); 
8 G) Z. Z2 Y T/* read result of initialization */ 7 T. }; y* S, `2 Z
errorcode = graphresult();
) b/ H0 \' E8 r V$ U" oif (errorcode != grOk) /* an error occurred */
' `0 L: V# U/ [, ]6 X: ~{ ( C6 M6 Y; T! Y7 v' L: w7 x8 v
printf("Graphics error: %s\n", grapherrormsg(errorcode)); / B6 `. N, i& W/ Y& P
printf("Press any key to halt:");
$ L8 \, P: |, I p& r3 |( `& hgetch(); 8 T% J( A" M" B
exit(1); /* terminate with an error code */
' h7 F9 {3 C+ a# Y4 _4 z5 v} 
% i4 u! I" O6 w+ u1 X. s8 j0 j0 e, {x = getmaxx() / 2; 7 r/ i, ~* g* o
y = getmaxy() / 2; ( w* t% k, @. W1 O0 ~; V
/* output a message */ x [0 ^% @: _2 ~3 ^
settextjustify(CENTER_TEXT, CENTER_TEXT); 1 v9 T' A! K! J! j2 ^, M% N
outtextxy(x, y, "Press any key to exit graphics:"); # y6 ]7 p+ p6 V0 N& H
getch(); 8 k& }9 [5 l0 s+ j1 ~/ e9 u
/* restore system to text mode */
4 U9 I r) N# `" @restorecrtmode(); # Y c' U9 m, q/ ~* [/ ?2 j
printf("We're now in text mode.\n"); 4 L! i0 x" m/ f* M' o6 ?1 G5 A6 W/ y
printf("Press any key to return to graphics mode:");
$ i1 {1 s: m, d3 \- v) ygetch(); ( c6 o- n1 W, B% M' ] h E* c: [% \
/* return to graphics mode */
5 |$ G- k0 M- k+ ~ J) f+ G/ usetgraphmode(getgraphmode()); " j8 _& q: z, p4 _1 C
/* output a message */ 9 i3 U6 W/ g. @9 K
settextjustify(CENTER_TEXT, CENTER_TEXT);
5 `% G# a8 h/ M7 Z' @6 \outtextxy(x, y, "We're back in graphics mode.");
+ b: O; M8 H# n! N6 I3 ?" y1 e7 }outtextxy(x, y+textheight("W"), "Press any key to halt:"); 
1 N' u( O* c+ _/ Z1 d! m/ C/* clean up */ 9 Z( G: d4 k7 z0 @$ Q" N7 o
getch();
 a6 U) ]0 K" f0 v3 H2 n; _closegraph(); ; q8 a8 M v0 `
return 0;
5 t) c* }+ q* K! C: y9 }" _}
/ a" \+ S. U# T' P7 v: I. b5 j! ~' L' ^9 ~

# T3 a7 E3 w& c9 m2 E函数名: rewind ; t" b" e2 A7 [; u5 D7 ]' |) v6 ~0 P
功能: 将文件指针重新指向一个流的开头 / z! E& o4 S: q4 g% [# B, i
用法: int rewind(FILE *stream); * S% k! P) w, u) E
程序例: 
: m, K0 w. W1 n0 R- C, R; z" A#include <STDIO.H>
* d p7 r4 ^, ]0 [' s ~#include <DIR.H>- }9 ^4 k% n, E
int main(void) + j6 ~3 m3 L; X! ~' ~8 c
{
) a" E/ C+ Y* O2 qFILE *fp;
% |# W! @! b; y/ echar *fname = "TXXXXXX", *newname, first; 
1 U' r9 z( [& Y( x% Y; C$ snewname = mktemp(fname); ) G" J# T* J6 ]" S
fp = fopen(newname,"w+"); ; ]/ a% H( F4 W
fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
# z- c+ ~" S/ F( Trewind(fp); 5 d" K2 a. k7 J
fscanf(fp,"%c",&first); 9 w e0 z8 G' L( W
printf("The first character is: %c\n",first); 1 S) x* X( j% y; u
fclose(fp);
0 ]5 m# i( E7 b+ Uremove(newname); 
9 m$ A# b# e# k2 [, `return 0;
2 J% N. U3 _5 u4 r}
6 l2 r7 d- x, u' I. ?8 y+ q; Q" ]3 ?

, E+ b F( r! E' P m4 u函数名: rmdir H. s c. e. ~: C' ^) B( [
功能: 删除DOS文件目录
7 ]. k* l4 `/ ^6 u& q2 Z用法: int rmdir(char *stream);
2 T" o8 w3 N& u2 h程序例: " E4 Z! U, y6 {9 {
#include <STDIO.H>+ }( c8 X$ x) I+ m6 Q3 }, N* ?0 D! {
#include <CONIO.H>, l5 {6 z/ ?+ X! M
#include <PROCESS.H>
1 x' ]% ^& z9 o& G, d) ^& n#include <DIR.H>
0 Z0 z. f2 a0 @$ r2 {#define DIRNAME "testdir.$$$" & A5 b* f6 v( l' D) L
int main(void) : m3 H) z! Y4 i; \, G1 c
{ . _4 W; o, H2 L3 W: q
int stat; 
) L! v% n$ q; `3 i8 h: @stat = mkdir(DIRNAME);
: I9 R& h3 s6 H, k; M+ y- Wif (!stat)
$ `: X- w" o0 Dprintf("Directory created\n");
 b: Y r. G2 l& b, q+ J0 r& Kelse 4 Y3 k0 x4 G' @8 y5 J) _% \
{ . ~) s! D& \, _) ~3 {, X5 o" W& I7 @
printf("Unable to create directory\n"); 7 D, |# F: F; f
exit(1);
" m" [0 Q# Y% q, k; m% Q" \, `: C. _} 
- t x! w) L3 r8 F" \getch();
4 u2 Z, n% R: Ksystem("dir/p");
" g' {% p U+ F; U3 agetch(); 
; o& Z5 |2 O" N8 L! g' Y8 ostat = rmdir(DIRNAME);
. m; E& g; h9 ~; Eif (!stat) ( o( N; n2 |# Z& f/ Y; Y
printf("\nDirectory deleted\n"); 8 ], ]# S4 i' V0 C; \
else ) x) c8 x5 h) U# V& D9 t
{ ^5 \) X( `! U/ L9 K/ }6 |9 n+ [
perror("\nUnable to delete directory\n"); + F8 P* ]5 K% n" T% i, S+ W/ k* F |
exit(1); / Y6 L+ C3 j. _0 g2 ^
} # K+ H/ O: S* H+ I% ]
return 0; ) d2 `7 X6 |( j' F
} 

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