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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); + `6 D+ }2 X) n* V3 @# i
/* restore previous dta */ . b1 m; I5 m' Q; w" Q( d
setdta(save_dta); 9 [; D2 U* p4 F5 k2 a
return 0;
2 J* q( q5 ~2 M" v) C, s} ( v1 j" G! Z: v6 @, F6 U& T; G
0 p9 F$ r" z# m, M3 C T
函数名: randbwr , o1 n7 r* A, v7 {4 f" x5 d
功能: 随机块写
* r: t' R! d, W5 ]( r' h用法: int randbwr(struct fcp *fcbptr, int reccnt);
. h( U% F& w% ~% E% B3 Z8 e8 K程序例: 
0 c t+ C7 P* H+ k* e) t% [) L#include <PROCESS.H>9 q6 S* Y! p3 _) k
#include <STRING.H>
7 H) ]( N6 r; j& [: y#include <STDIO.H>
/ Y# R, s$ S/ X3 f# w1 ^5 \#include <DOS.H>+ Z2 e9 B1 t$ r
int main(void)
8 {- `8 y: }3 A! N{ 8 ?$ T7 {, L- W
char far *save_dta; , T9 D0 B: y8 ]# _* V
char line[80];
7 ^) r0 r$ m" L' P7 U$ A/ ?char buffer[256] = "RANDBWR test!";
4 X% N! i* `; y. t; E Q2 Bstruct fcb blk; Z) i- A2 t# g, _ s* {
int result; 
1 g) s+ s0 o4 ?- i! F/* get new file name from user */ % @% I# i3 U3 t, O2 q
printf("Enter a file name to create (no path - ie. a:file.dat\n");
% U6 U& y+ ~+ S& i& r+ @ W Dgets(line); 
; A4 @8 V1 x0 I6 \1 I- u+ |' W% m/* parse the new file name to the dta */ ! Q. N9 ^# Z" B" i
parsfnm(line,&blk,1); % n2 h2 T2 }0 l* ?+ {, G
printf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
 ]8 Y( p" `6 \6 M+ x6 l7 X+ M/* request DOS services to create file */ ' b8 }( W9 p) Q4 _; u
if (bdosptr(0x16, &blk, 0) == -1) ' u9 X5 }6 m ]2 T+ A" {
{ & z0 k6 q6 d9 ~8 n4 n5 Y* B
perror("Error creating file"); * Q# N6 i# o3 v( X
exit(1);
) {$ j4 H0 A, S8 ?# a1 }, T$ i6 a% J7 x} 
4 q8 r7 i( d0 i5 Q9 m- t, o/* save old dta and set new dta */ # c& X2 V* w, J
save_dta = getdta();
# J6 G! P) t, m: ssetdta(buffer); 
5 A0 G& W( k5 h, C/* write new records */ " i- d! E* {& ~" x
blk.fcb_recsize = 256; 2 b( n% | {" d; k. ~5 d
blk.fcb_random = 0L;
/ B, _- J, Q* O9 L) j/ m, @result = randbwr(&blk, 1); 1 v7 n$ l, P9 e: s8 r
if (!result) 7 S- {0 j$ l6 I/ n d% U- f3 Z) j
printf("Write OK\n");
, h$ w- {: b; U6 |else 4 e3 F% X6 W D% A" c0 s- m
{ ( @" F( |5 y( }5 }+ I
perror("Disk error");
/ Z# z) Y: N* U; l2 eexit(1); " C- O# Q( m6 l4 w, m
} ( p. B* U0 @' k: `7 f, K
/* request DOS services to close the file */
9 s7 L- h- F; oif (bdosptr(0x10, &blk, 0) == -1) " Z5 I0 V3 U* v- t. F
{ & I( I4 I( v. A" M
perror("Error closing file");
9 i9 j6 s s, b4 `' nexit(1); - ?3 x$ ~1 ~, e5 e1 o8 U3 U
} 
0 z; @' q) u2 b, j/ |% i7 b9 {/* reset the old dta */
' o; O1 q0 r1 P9 D5 r) asetdta(save_dta); 1 n( H- p) }7 F7 F3 J, q4 y" y
return 0; ( K! n9 K0 D" [$ C' d2 e
} ) v3 P/ Y/ E/ _

. a* `9 v5 o: G* ~( k8 C3 o. H0 z7 i8 c
函数名: random , d5 d r4 _0 t" z3 P0 S
功能: 随机数发生器 % M9 ]& }9 P; z( h
用法: int random(int num); ' Q' ^0 _; U. ~
程序例: - B4 ^) x' g. t3 |
#include <STDLIB.H>
- I0 H# u5 O; ^# o) x, E#include <STDIO.H># ]2 O" N+ [9 b7 W: D2 h, G
#include <TIME.H>
! _9 [9 Z. y O( Q) A$ x/* prints a random number in the range 0 to 99 */
& w) y$ P' P; y& B* fint main(void) + G ]4 ~2 k; y" M' @
{ % g4 R9 ^- G8 Q$ b5 w
randomize(); 5 h. U( V$ b9 _ y+ I! l) T! k! a
printf("Random number in the 0-99 range: %d\n", random (100));
/ q, N9 H# g) Z9 \8 k" t2 H [return 0; + i2 ]1 _, ?! n4 ]
}
: J3 x5 ?1 i/ H" A/ |
' ? I6 \2 `2 T% W7 C+ N% }. k& c5 h9 ~
函数名: randomize * {3 h+ C% N; K0 u! X1 Z1 d
功能: 初始化随机数发生器
4 b" n6 o* A# u* [/ m b用法: void randomize(void);
. F3 ^& K9 L) v, S9 k程序例: 
 e- @- F5 v( h/ o# s; S#include <STDLIB.H>
" e" y% G9 C5 K#include <STDIO.H>2 B. O% q, m; _7 H! S3 t# C# @
#include <TIME.H>: R" V# Z# \6 G
int main(void)
4 y9 O- |3 o' V/ ^ b{
( f2 } q2 G" a1 {6 ?int i; 0 H3 s* n( @, Q
randomize(); $ V% Z! I+ `/ J8 b7 U: }( b
printf("Ten random numbers from 0 to 99\n\n"); % f1 P6 z2 }9 e8 ^* C, T6 y
for(i=0; i<10; i++)
' L x1 U$ |2 o0 W/ M: m# b- Hprintf("%d\n", rand() % 100);
7 x$ x$ H' R5 t- Creturn 0;
" R7 |% e9 Q: C. H' W0 F8 ?5 g}
5 t2 @' z( j6 R `( {9 ?( ]2 R. v

4 {5 |+ o" ^$ Y9 n7 v函数名: read 
) B2 X# W# }, ]$ E功能: 从文件中读
( ~# |- V: E1 i5 [* l0 g用法: int read(int handle, void *buf, int nbyte);
* J! P/ t5 V1 w8 s0 G程序例: % N* |# H* y% D( W1 m
#include <STDIO.H>
' p6 N! g% F5 J; N; @#include <IO.H>! n! A" h- O8 ^- g3 I
#include <ALLOC.H>
% ?+ S- n4 c! P+ F4 I' z4 P#include <FCNTL.H>
' W' M. Z ~5 x5 Q! \* i#include <PROCESS.H>& a* v( U5 A3 Y, A$ I* @+ X
#include <SYS\STAT.H>
( v, P# ^: B1 x" Y$ o9 q I3 r( Zint main(void)
2 K- S) { c% P{
! v/ y8 C: E6 ?; rvoid *buf;
# N' Y2 _) F* j( w8 Lint handle, bytes; 
- T ?: O9 ^2 `# E# _, @buf = malloc(10); $ D+ I3 y0 T- ?! F4 v7 L, \" I
/* 2 ^% E+ ?# p. G$ [) V% J
Looks for a file in the current directory named TEST.$$$ and attempts
! n( ~5 D, k' @. B) T+ Tto read 10 bytes from it. To use this example you should create the : V9 m" B) r, _. e4 S. ]- L
file TEST.$$$
0 M2 x' h4 D. p; t5 P. p*/
( W$ c5 A1 L4 @# Z' z5 vif ((handle = 0 _' b% u0 U; z* h m* x
open("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1) $ h; F- U* {8 F9 F$ J
{ ' t; r( H4 H4 {8 W
printf("Error Opening File\n"); L$ v/ f+ H0 R0 t# m, a
exit(1);
. J* Q5 i- g0 w5 F) y# ^} " ?( c6 h) Z! U: C4 q
if ((bytes = read(handle, buf, 10)) == -1) { * r- f ?/ z# e+ e2 |
printf("Read Failed.\n");
, g) S/ j, C' aexit(1);
1 C$ A# ]2 B8 l! W' o} - z0 D3 v8 A4 y9 B/ v
else {
/ a O& O$ W( n7 n* f6 Tprintf("Read: %d bytes read.\n", bytes);
; a/ O7 z* G! M/ @% E, g' S9 }} + ^. X T! t7 O
return 0;
7 F8 g5 ]* X; B/ G+ z5 _} - e+ ]. k3 P% u. z

; r/ @. w' Y6 d8 O1 d. T
0 S* u: B' L+ ^- ?4 S4 T函数名: realloc 
# j) {4 g6 n0 K/ x( K功能: 重新分配主存
6 S' W, W% j7 ^- Q& M) N$ o用法: void *realloc(void *ptr, unsigned newsize); 0 a+ ]* f: H$ g3 X# G4 K8 M
程序例: 
4 O2 P+ s D6 C0 S4 z#include <STDIO.H>
7 e k8 O, W. e, |9 [5 _" T: w#include <ALLOC.H>
9 O/ T! K1 E' _7 c% K, P4 H#include <STRING.H>
7 R; s; k# S6 J* n# ~8 kint main(void) 5 V! o% @& u& O
{
: s8 j( G0 h* e( U* q: Q/ ]5 W/ ychar *str; 
% G- f1 R# S+ P* n. y- v# t/* allocate memory for string */
+ s8 A q/ @* @, `. Ystr = malloc(10); 
3 ~9 [' k; @+ E7 k0 U/* copy "Hello" into string */
2 A0 ~. k/ ?9 x1 Z* o" hstrcpy(str, "Hello"); ) Y1 o8 L% e/ ~% @; o
printf("String is %s\n Address is %p\n", str, str);
str = realloc(str, 20);
* d) q/ u" t6 o& Y/ E; p k: Iprintf("String is %s\n New address is %p\n", str, str); 
( q% t0 d# P/ z* n8 q# f/* free memory */
7 L/ J4 P* [! ~* Cfree(str); , i1 }& @( v3 C# f: x
return 0;
, M" i" D8 q, G) X7 U}
3 v; t: R0 S3 Q, m" R8 L i2 K$ z" ]9 g5 S2 |- j _

7 o& n4 \. I0 F/ q函数名: rectangle 
5 t- J* _1 J4 _' }功能: 画一个矩形
5 ?, p6 [0 C4 F: R i7 p用法: void far rectangle(int left, int top, int right, int bottom);
# U9 Z5 k) c/ L. v2 O程序例: 
( t7 Z9 D# }$ K% [ x1 w#include <GRAPHICS.H>4 K8 E( \* D$ s; H9 L% z9 K9 T
#include <STDLIB.H>
/ J1 L0 P# y: R' A2 T& K#include <STDIO.H>
; V% I# a- \/ G: m& p, ?% W#include <CONIO.H>4 L! B/ k& w1 ]5 M" H1 H- E' j# f
int main(void) # t/ \1 y1 }4 Y2 K
{
, }* }% P1 g" u/* request auto detection */ 2 m$ n) E5 L- r0 F) t
int gdriver = DETECT, gmode, errorcode;
2 l: h- {: M% Y3 o8 tint left, top, right, bottom; " h( y4 @4 ^* X0 y' j' e" b
/* initialize graphics and local variables */
4 P" ~# j& m! Q2 {! r) e! finitgraph(&gdriver, &gmode, ""); 
# i8 R# ]; X( X2 C& A; k/ k8 d9 E/* read result of initialization */
$ ]2 {- Q; U- Cerrorcode = graphresult();
' w, W% y9 ?1 A0 c7 L' F( bif (errorcode != grOk) /* an error occurred */
. p; ? v, | g3 h E{ 4 ~' l, Y% {( E1 |$ U
printf("Graphics error: %s\n", grapherrormsg(errorcode));
4 [" C$ F3 w0 D# K$ _( m& Xprintf("Press any key to halt:"); ! x6 F g9 F7 c! F" y: f( D9 c9 N1 s
getch(); - b' E8 m, o/ V6 ]+ ]) \9 W7 w w# g
exit(1); /* terminate with an error code */ 8 y& _5 ^6 L# J; j! r
} 
! q# n, Q: K) m2 p# Q5 ?left = getmaxx() / 2 - 50; ( }3 `3 C0 x9 {0 G. r- E- k
top = getmaxy() / 2 - 50; 6 g$ O& }- [+ a- H/ N
right = getmaxx() / 2 + 50;
, V: H F" r0 ~9 y( Lbottom = getmaxy() / 2 + 50; 
* r' T3 a) F" O4 H/* draw a rectangle */
" o$ }0 N& ]" Xrectangle(left,top,right,bottom); 
- c/ V) L3 ?; _# j6 K/* clean up */ $ N7 q( ^1 P: Z
getch();
) s3 N8 a2 d) c, |# bclosegraph();
0 K# U0 Z/ j5 }return 0;
8 P8 O. O ?4 X8 e9 {7 M7 r} 9 e+ v; T0 }; a# Q( x
0 ~& a* j. @- a

 j- W9 J, S# a D+ C9 L) q函数名: registerbgidriver o5 I- v, r' g2 j, U; }
功能: 登录已连接进来的图形驱动程序代码
. V( \, Q- V: v. Z v4 Z% F用法: int registerbgidriver(void(*driver)(void)); : ]" ^9 a1 q( Y& ?
程序例: 
" V) Y$ e" B) {$ s#include <GRAPHICS.H>' w4 [6 Z& X) _2 g# |$ F- E, H
#include <STDLIB.H>7 y4 Q2 _# j* I7 R. V4 I$ U+ l
#include <STDIO.H>5 [8 _: n; j( u2 s9 }; H( g
#include <CONIO.H>- j% c T0 Y# j/ p, V! ^
int main(void)
( q8 X0 N* a6 v7 L3 @: ~{ ; Q& T" a* W b4 s. f
/* request auto detection */
8 Q2 ?3 K# h! h9 f6 Q- Dint gdriver = DETECT, gmode, errorcode; 
/ x2 @2 i) z0 z" t7 `/ b/* register a driver that was added into graphics.lib */ ( g; a9 S+ [4 Q! ~, O' ?! z ~
errorcode = registerbgidriver(EGAVGA_driver); 
4 _+ H4 f% u( T- h, [/* report any registration errors */ " j& D J' O( O$ Y+ i! b) E9 Q
if (errorcode < 0) 6 E& R3 U; A, c6 t9 {1 x
{
9 b0 K3 Q& o9 e1 Y% B" mprintf("Graphics error: %s\n", grapherrormsg(errorcode));
: X7 a. P8 j! I0 i/ [: gprintf("Press any key to halt:"); ' p. ^, }7 _( F7 e5 F3 \7 j( D
getch(); & I8 X# F& N8 H l3 D+ h5 I
exit(1); /* terminate with an error code */
/ J2 d' p- h8 t+ P, q/ S7 [& o* P} ! `- S" S# N: x; ^, q
/* initialize graphics and local variables */
% X( D8 m7 n" qinitgraph(&gdriver, &gmode, ""); 
* T6 M7 q& M L) E- x% x/* read result of initialization */
4 R. q: m( O& J7 serrorcode = graphresult(); $ Q: Z' }- Z6 \9 J; o* O/ N4 l3 `
if (errorcode != grOk) /* an error occurred */ & H5 c ~- a. t) f5 ^
{
; `0 l* U9 B# w+ ^! ]0 ]2 Z1 E/ nprintf("Graphics error: %s\n", grapherrormsg(errorcode));
0 F) ?$ r( T S5 \+ nprintf("Press any key to halt:"); - R- }3 l, [! H
getch();
/ |& D( ^- C0 |5 H6 Vexit(1); /* terminate with an error code */ ( A( k1 m7 G' f
} 1 ?2 J/ G, v* P4 K; R
/* draw a line */
1 Q$ i9 b* N1 a( ?6 O# tline(0, 0, getmaxx(), getmaxy()); 
1 b% Q" N6 N! U6 g' b$ O0 N/* clean up */
! Z/ s/ ]9 z9 Q2 K5 A- Ugetch(); 1 B9 h! f6 C6 {
closegraph();
" Z' s2 ]$ z6 \return 0; , i' a3 Y2 Q" z- h
} ! i& A2 d0 l# r
4 D6 g( v% t8 s( O4 g

' l& _# P$ z' }) o函数名: remove 4 t5 x9 ]% q/ O/ G2 y, S
功能: 删除一个文件
( b5 G. M0 i& U c5 L& W& h用法: int remove(char *filename); : [: C2 {0 u; R, [& V; o& N
程序例: 4 f, W# `* ]8 s$ l' ^+ f
#include <STDIO.H>
! {! h! f/ y! e4 oint main(void) $ a& o q0 t( r: `: t" k. ~
{
% |4 w( S: [& j! m5 t' uchar file[80]; : Z2 u" t+ S/ e5 s1 r# D- N
/* prompt for file name to delete */
- j8 Q: h6 h; k8 ? v) ^( Hprintf("File to delete: "); , @9 |4 ]5 [9 a: @- Q4 c/ p6 r/ T
gets(file); / t6 F" ~( X% n( A# q
/* delete the file */ ! J& `! n( ~# A/ K- j/ j$ ?
if (remove(file) == 0) / Y8 A F( \% j& f' L; \
printf("Removed %s.\n",file); $ q. `* l# \4 @! j% O6 `9 T
else 7 u; }5 Q9 l0 {
perror("remove"); 5 P/ q. m# g; z' f3 ^ e, M0 U. L
return 0;
" a* l( o$ G& p$ H}
- L; s6 Y+ C/ w# j: |
$ L5 ~% g5 }; h: s0 q, I1 W
 F' C6 X5 D/ T* r函数名: rename 
! e/ m) j/ P+ s! l ]9 z5 D: {功能: 重命名文件 ! O5 }1 W" G: g( v* k. F' Q( `
用法: int rename(char *oldname, char *newname);
+ \' y; q4 A, z* P程序例: 
( x8 }6 j: A* Z& \1 {#include <STDIO.H>
5 C' K9 I* ~! E, y, ^int main(void) , c: m$ R) h5 U7 e7 `( n
{
' Y8 a. Z; T' t1 ]0 v- I" zchar oldname[80], newname[80]; 
& r. d9 [3 ~6 \5 v/* prompt for file to rename and new name */
$ N" l( m/ Q2 m+ o, g/ Oprintf("File to rename: "); * @$ o. ?5 n6 b( M
gets(oldname); - F7 p+ _( [8 g/ g
printf("New name: "); % X% x! ?+ j0 Q T2 o' R
gets(newname); 2 ^* k4 y# ?2 V! x6 m, w6 Y
/* Rename the file */
/ ]3 D% x7 S/ `! T. Qif (rename(oldname, newname) == 0)
2 \. [% V0 t1 n, G& }, _ W, Yprintf("Renamed %s to %s.\n", oldname, newname); 3 R E- a* ?$ ]
else 8 s' G! M1 j) j* e- ~) |
perror("rename"); 
5 w2 X8 X) r2 Z/ h# E, Breturn 0; 4 F0 \+ N; | G; }$ `; D% s- i' A
}
' _: [8 e1 Q1 H0 r8 k, b8 {0 q$ z. v; a8 C h; v0 V! @: k
3 M' M! e! Z) @9 a2 ^8 o/ y. I! x
函数名: restorecrtmode - O! I$ c9 F/ w/ D) m
功能: 将屏幕模式恢复为先前的imitgraph设置
* K( V* @, c- `用法: void far restorecrtmode(void);
9 b+ c+ X4 k8 S6 s. i程序例: 
0 q% P& V6 ?: `9 z#include <GRAPHICS.H>0 _ @3 }5 ^' d. }
#include <STDLIB.H>( i4 ]. L: p# z
#include <STDIO.H>' N @- T0 E x9 J z4 T
#include <CONIO.H>
; F; \ C7 B# \0 Eint main(void) % |& w# M7 K0 b; M
{
" t* Y& d9 M. f5 I1 J+ e/* request auto detection */ ( a- ]$ Z" G5 S
int gdriver = DETECT, gmode, errorcode; - T* @0 J* C- i. f
int x, y; 
4 I$ S( X. k3 D. L' `$ C& ?/* initialize graphics and local variables */ 2 ?8 T7 T7 o- {/ Z
initgraph(&gdriver, &gmode, ""); 
+ P+ P, y* ~- H8 n7 [9 C, m/* read result of initialization */ % b: j2 Y1 n a8 C2 C: V$ c
errorcode = graphresult();
- m2 h+ }5 ~/ i6 ]0 A4 X; |. @if (errorcode != grOk) /* an error occurred */
+ {0 ~* z) l" j% j& h6 p{ . r1 o0 x8 c$ O4 [# ]- j+ z8 J6 Q
printf("Graphics error: %s\n", grapherrormsg(errorcode));
, f9 Z/ I1 d6 gprintf("Press any key to halt:");
/ H0 w/ p" |' @# ?( ^( X. j. _% e% @getch(); ) U( C3 F9 z6 u* N y6 R
exit(1); /* terminate with an error code */ 8 F: Y6 u# i- K. Y J
} 
2 g0 p8 T5 O% h- X5 k1 yx = getmaxx() / 2; 4 A! Q0 E2 R5 y; e, j- J9 a* }. ?
y = getmaxy() / 2; 
& O8 U5 t2 a% J( t. Y/* output a message */
. S: D3 s4 V% k+ `9 U fsettextjustify(CENTER_TEXT, CENTER_TEXT);
! `6 j' v g l! ?1 v- bouttextxy(x, y, "Press any key to exit graphics:");
+ E2 z9 \$ a5 M* ]7 Ygetch(); 8 k& r) g4 D! }
/* restore system to text mode */
; [! K5 |' N- n9 [, Brestorecrtmode();
% C8 n6 \9 m, @1 o2 \* |printf("We're now in text mode.\n"); 5 K. H5 p$ A& i9 B/ F- A( Q
printf("Press any key to return to graphics mode:"); 0 o, ?' t- I8 b O
getch(); 
$ B3 z4 m% _: U( |/* return to graphics mode */
+ l; a, O1 z+ v7 U$ isetgraphmode(getgraphmode()); 
7 j6 }9 t1 Q1 e. `# h4 f/* output a message */
# ^. G5 K# ^; t* `3 `# Nsettextjustify(CENTER_TEXT, CENTER_TEXT);
3 b q r) R1 g. {/ o* vouttextxy(x, y, "We're back in graphics mode."); ) c' j! Y( D: O2 a' I
outtextxy(x, y+textheight("W"), "Press any key to halt:"); & Y% K. E7 R' o' ~. x
/* clean up */
0 y6 q- [; N0 @ c; k# [; Egetch(); # X, m" j9 m( S0 y4 H
closegraph(); * I" t: y8 U( a. e
return 0; % D1 ]( Q/ X& l5 V' r- D
}
1 w# n+ ~* O+ [2 a% t1 p6 ~7 [+ U! M; H4 c8 m1 X

* L: v( k9 u( ^- W) `2 y, A2 g函数名: rewind 6 }/ p9 v4 u. B6 _/ ]
功能: 将文件指针重新指向一个流的开头 % c0 h/ {7 N7 d! Z
用法: int rewind(FILE *stream); * p7 l+ k Z: x6 { X% F5 ]
程序例: 
6 C! A+ R0 t% G: c4 O0 D#include <STDIO.H>
0 S/ K; P: ~8 J. ?: S5 i2 x#include <DIR.H>
4 [! I, l( s) X! Z% u$ ]4 v9 I/ Eint main(void) $ i" Q5 i1 ]1 j! h! C+ j0 d8 Q
{
2 f9 p& n4 c5 O" {6 P6 E# i- k' XFILE *fp;
- e+ h9 }$ j9 j% U# Y [/ Z R+ ochar *fname = "TXXXXXX", *newname, first; 
, E0 i5 w+ v# M6 ], mnewname = mktemp(fname); . c$ W0 B( }( l/ d7 n, q5 t
fp = fopen(newname,"w+");
- |! a; t( A4 w+ `( I% E7 V2 y5 k; kfprintf(fp,"abcdefghijklmnopqrstuvwxyz");
8 D/ D% E/ X9 D9 F. u$ g1 yrewind(fp); - v M2 A$ S8 r& a
fscanf(fp,"%c",&first);
) D7 D/ {" J0 d+ Dprintf("The first character is: %c\n",first);
+ z' w k5 @+ w) v2 i0 p! {+ @fclose(fp);
: \3 k$ ^. z! S4 C& ]remove(newname); 
0 K/ O* [8 Y7 G& Z( d! P9 j4 Treturn 0; 6 x# u% k/ K$ I" O' g: A6 y
} 1 M$ J- v4 a0 H9 c' A6 u8 D x) X

% ^2 B& X( z/ l# o; S7 i! }
# i1 I# {- r; O- l3 v' @函数名: rmdir 
8 Q. }) M/ K% M5 M7 ?功能: 删除DOS文件目录
/ Q2 Q: ?9 Y3 b0 s8 S" F用法: int rmdir(char *stream);
 |' P% h8 b8 s; M程序例: 
$ w' M9 u4 w4 }#include <STDIO.H>
; ?' z' Q5 k8 G6 I#include <CONIO.H>
* ~/ K* N! ]4 m3 R! N#include <PROCESS.H>0 k9 Y, B8 p! S+ Q$ j
#include <DIR.H>
! A6 p8 s* t1 D& d#define DIRNAME "testdir.$$$" 
8 R* }% `2 |% g6 N* d% W! g" Hint main(void) / F2 B3 O9 J9 \. o' k2 ]# S' q* T
{ & `% O2 e& @: u# \5 g
int stat; 
2 M) R5 j" g! {5 `& s8 S* fstat = mkdir(DIRNAME);
$ \' ?% Z( U) yif (!stat) 4 n+ p0 l& {, c
printf("Directory created\n");
& _' x$ A: L- `2 v3 I/ S* o% belse 4 c, N3 Z; u0 T3 H# ?
{
* m6 O4 T/ I0 N4 F7 U" c0 Jprintf("Unable to create directory\n"); 2 S' ~9 U+ n: ]% T9 F9 P
exit(1);
8 h9 z# S" R! q! ~) d/ i t9 k2 M} 
! Z. m5 b: G; z& H: E* P1 \+ rgetch(); ) w$ g0 H- `% G/ s: A8 ?" s' n
system("dir/p"); 0 R0 q7 p! L2 t( c% I9 S/ [
getch(); 
' y+ d; d! L, M3 d* M; p# dstat = rmdir(DIRNAME);
 z) @4 j# r; D, U$ ~if (!stat) 1 u7 S) @+ t2 t6 p% q/ d& ~0 d
printf("\nDirectory deleted\n");
2 m9 }, `! ?1 ~. K% q8 C! l) Oelse
1 O$ {$ V( F1 h: a' K- S{
. |* z1 x8 U$ ^) [/ }" X6 ?6 Rperror("\nUnable to delete directory\n");
6 ^8 Y/ ?; {( h1 ]: d3 B& [0 Gexit(1); ( k2 u/ [' `5 q/ r
} 
1 D1 V! a2 @; K3 greturn 0;
9 h. e( x6 v+ W8 i: A9 [+ z: e% {}