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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 |正序浏览

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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); ; D. x/ x0 g# d3 c ~: f1 t k
/* restore previous dta */ . f8 \$ s) ~: E+ m" V4 D6 [
setdta(save_dta); 8 `, }# E/ X. ?% R3 g5 a$ ~
return 0; / n$ a- b# o- e& ] ^9 t
} 5 k7 t' s4 N) f8 w- }2 p$ R2 g# c
& |% t2 ]4 y( [
函数名: randbwr 
, K. c+ k3 }( o4 y& `1 x1 _功能: 随机块写
, g% p3 @4 G4 g' o( g4 g用法: int randbwr(struct fcp *fcbptr, int reccnt); ! O# V5 o/ ~% L
程序例: ! W/ A# d4 h5 Y8 k* u) Q; h- y
#include <PROCESS.H>- s3 t8 t; V) ~
#include <STRING.H>4 L V6 e" F* Q, L- a. B# b1 E
#include <STDIO.H>
' }1 B- F H4 P- {% M6 B#include <DOS.H>
. ~* B5 ~% z/ g! o. wint main(void) 1 b7 [6 ^4 W- n4 a: Y) I* @
{ ) k: d& E7 g1 P0 @9 F ^
char far *save_dta;
$ W2 P4 r: Y( G; Qchar line[80];
4 c' M0 a& M# ?: {4 [char buffer[256] = "RANDBWR test!";
% X1 m0 D9 q4 ~- K `' v1 P2 jstruct fcb blk; 6 i- q0 ?; d1 U+ N0 Y4 H
int result; 9 e4 k* L9 D0 A
/* get new file name from user */
5 q/ D2 Z8 Y' Y' ]2 Q8 O# P7 Oprintf("Enter a file name to create (no path - ie. a:file.dat\n"); . D# @/ M1 C$ h! m7 [' ?0 j
gets(line); + ? H7 l8 `/ a% _9 h3 e
/* parse the new file name to the dta */ $ h6 ~2 p* x7 ^
parsfnm(line,&blk,1);
 w; c" n7 Z% U! Gprintf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); : d6 d. I8 \' ~
/* request DOS services to create file */ 7 ~, Q* k. v2 F( S: G
if (bdosptr(0x16, &blk, 0) == -1) 4 h- i; F0 O7 \1 e
{ 0 p# s' i2 ]' @3 d, S
perror("Error creating file"); 1 J$ {1 y5 V6 ^- X$ l: I8 O
exit(1);
( y( y- `* M7 p4 U4 s: v} 
+ S. M: `% m$ ?. ]. `1 l- ?/* save old dta and set new dta */ 4 l% [" T/ S9 ]; t' ^9 G2 ?
save_dta = getdta();
# a y7 k& b5 I7 q, N3 l, wsetdta(buffer); 
) `; h* b' F* D) o7 Q( U9 w/* write new records */ : V( P" P' V! v
blk.fcb_recsize = 256; % o+ x1 u2 ^! C# F
blk.fcb_random = 0L; * R9 @+ a0 \# u' H' \* n! g& j
result = randbwr(&blk, 1); $ w$ Z" I/ c. o8 j4 v2 f3 t8 X
if (!result)
) D* O% h3 f7 k9 S$ c# [printf("Write OK\n");
6 }$ Z5 W4 g9 `- Uelse 2 h& b- |7 t5 a
{ 8 w+ @7 ~! |! R! D1 h
perror("Disk error"); % u: G" W2 [6 _+ r1 O3 A5 |$ _
exit(1);
+ H( i/ f2 W8 S/ P7 I0 J$ B} # _+ Y2 a% F# [. Q( J K* v
/* request DOS services to close the file */ & l; ^9 A; H! S" O0 {; i
if (bdosptr(0x10, &blk, 0) == -1) 0 J; S, A9 A5 k& [. v
{
; W, A, O. |# [3 y4 Hperror("Error closing file"); 9 D! T' d4 T; f) s+ y% m
exit(1); 4 N& X9 q0 H& H9 F" [: A
} p# v* b b! `9 i) E- b# |
/* reset the old dta */
& g+ t2 D4 K6 \+ {setdta(save_dta); ) E6 E: u9 p2 U2 s) _* \& k" ^
return 0; ( K1 E- J/ v" K/ |$ }; x3 N! T! X
}
# U4 I, V$ p2 t& G7 q k" X1 P# Y! g5 k! \: n! g' B3 r5 D9 _

: A/ I M" ]$ V7 V6 ]函数名: random 
8 K1 h4 G' I4 {5 w功能: 随机数发生器
/ F, L& M& L' C用法: int random(int num);
0 [; ^3 z! y) w. C8 K' l程序例: 
! V2 N3 E) ]* T4 w. I& V#include <STDLIB.H>( ?9 o/ |/ T# n3 F5 }' ]4 @0 m
#include <STDIO.H>
1 A) L5 L- D! m7 M0 e#include <TIME.H>
" Q& x/ `3 ?3 c) p( J8 D/ p' M9 l/* prints a random number in the range 0 to 99 */
4 Q6 ]; ^% ~5 G" p7 d3 y; Nint main(void) : E' Z1 w; F. B0 o3 V
{
, x( `6 p+ z" r8 Erandomize();
4 p' Y' K) y ^' N7 X, X- fprintf("Random number in the 0-99 range: %d\n", random (100)); 5 [' Y: k+ P2 B3 Q! }7 f
return 0; 2 s8 o, `5 p8 b6 H
} * `7 }$ [7 E' b* P. c3 Y
' L0 |$ ?( \. n' @* r8 f3 r# Q* q! j
! k' M( L" z* H/ l; d
函数名: randomize : e) f7 U/ d G# w# i; N2 F
功能: 初始化随机数发生器 8 I* t+ x0 L* V& M0 H
用法: void randomize(void); * P/ X$ B: t: k; z/ i
程序例: 
9 e1 k. y) m1 u# n8 ]. i/ ^+ ]) u#include <STDLIB.H>0 O% X2 ^( z9 K
#include <STDIO.H>
$ q5 M0 Z8 D; m5 E* l#include <TIME.H>& a" h& s. E" U5 C$ X) ?6 q
int main(void) " P* h: P, \# U
{
0 g m1 C0 k1 m# `3 z1 A6 I9 Vint i; 0 b6 r( M _5 j- M% s/ P! R
randomize(); " K5 }1 w5 w" X/ f3 D
printf("Ten random numbers from 0 to 99\n\n"); 7 f9 D6 d2 g1 x1 X" A1 m6 I
for(i=0; i<10; i++) 5 u9 Y" c) n+ G0 i
printf("%d\n", rand() % 100); " S' `: I$ y+ b6 D( E& P
return 0; v; N! j, y1 @' e: T3 [2 I5 A) @
}
' b, D6 L3 h% [1 u1 f" w1 L7 f# h1 r" Q4 Q9 S" w$ X
: c# H" A& R- X9 }
函数名: read 
$ z: A% k4 W- t功能: 从文件中读 8 ~ j1 W$ N( I8 R) U9 Q1 F
用法: int read(int handle, void *buf, int nbyte);
 D" u3 A" h2 R0 | ~程序例: 3 G7 M, z- a2 T: o8 C
#include <STDIO.H>( X% f$ h0 \! S" D
#include <IO.H>
( W R4 R$ J1 ?9 x. Q#include <ALLOC.H>9 \. R$ C# ~3 r5 N7 `4 X* u( b
#include <FCNTL.H># p V$ k# b, T! ~7 f5 v' s$ |2 v/ W+ F
#include <PROCESS.H>0 L$ v+ N/ a, |0 c5 S0 ?& l# {4 V* B
#include <SYS\STAT.H>
0 T- z( I+ S9 ?# tint main(void)
( F3 U" H- H7 ?7 {& }* G" h{ " ]5 @) i) O, o$ a( `: n
void *buf;
- n+ P* t$ v! {" Kint handle, bytes; 
/ O5 E4 K g2 n9 t3 b& ebuf = malloc(10); ) D1 E6 u$ t$ Z
/* N" z, a) a1 b8 {
Looks for a file in the current directory named TEST.$$$ and attempts ; o% o9 m8 \7 C7 C, f* e
to read 10 bytes from it. To use this example you should create the
& L8 @5 ~( Z+ j; {6 w3 g/ p3 N: dfile TEST.$$$ 7 h! M g* g* Q+ E$ \
*/ * d1 p/ i3 ?+ O7 N; S
if ((handle =
2 c/ z; Y# O% ^2 q0 uopen("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1) " m u- A9 H: j# E
{ 3 e0 g8 _4 M4 C) I- `
printf("Error Opening File\n"); ; x6 v' F* {) B, a
exit(1); 9 w# T* q& C, W2 O5 X) W: M
} , b, u7 v+ P& D, u
if ((bytes = read(handle, buf, 10)) == -1) { / M; v" k4 t7 H0 t
printf("Read Failed.\n");
1 g* [) v& u! B qexit(1); : C- m H) y+ x! F7 K6 o
} # y K/ Y9 x$ O. K5 p' J0 K
else { 0 }5 c+ f2 W' ]0 E' B+ w
printf("Read: %d bytes read.\n", bytes); / W2 T/ Q7 i, \9 W/ Z
}
- \9 ~, \3 L. [) n; Q) b* Creturn 0;
( x& G3 f, Q: _5 x} 4 s$ {7 m7 O' l& d; U% u

' l5 V' ^- x; W! _; W
! [/ R" M+ Y1 T' o0 m函数名: realloc 3 c3 I4 r b4 x
功能: 重新分配主存 : J9 ^3 r, A& h
用法: void *realloc(void *ptr, unsigned newsize); 5 O, [* V+ L8 ^! S1 o
程序例: 7 m' T% w4 x% D2 ?: m
#include <STDIO.H>
$ `) k! g8 k. Q; \#include <ALLOC.H>
0 P! @- j* Q; k" v' u* F#include <STRING.H>
: N( n- t4 T7 l$ S. }int main(void) 7 i( Q( i$ \' k1 p# a3 W
{
$ {* ]& t2 K* ]. Y8 P& v! ychar *str; 4 F3 s1 k9 Q }$ v5 V2 {
/* allocate memory for string */ ) X \' ]2 [2 g5 W+ a. E
str = malloc(10); 
+ I. C# l2 w& V# `0 Y' r/* copy "Hello" into string */ 9 [& e/ n1 f+ |; A9 Q K% t: s
strcpy(str, "Hello"); 
- w2 N5 j5 `$ x# ]5 X7 Mprintf("String is %s\n Address is %p\n", str, str); 6 n' ^ P0 v. B, u H( |1 p* }
str = realloc(str, 20); 0 T$ ~) k) p, s
printf("String is %s\n New address is %p\n", str, str); 
$ W0 o3 ~4 D# o% V/* free memory */
3 V/ d% g0 V9 U0 ofree(str); 3 i. w6 b3 ^" g* X' Y. S5 H: Z
return 0;
6 `$ ~: m1 t7 w1 i}
. i1 f3 k4 ^( Y+ i0 j' _
3 d* ?6 L0 e1 m4 s2 E
( B# d. C( J/ T6 ~/ v' S9 t. o8 _! _函数名: rectangle ) }% i, K# y; y& I! j# P( C
功能: 画一个矩形 5 ~7 v* [/ [" V5 p& F0 t
用法: void far rectangle(int left, int top, int right, int bottom); 1 p8 f- q5 x% L$ j( x6 P
程序例: , m" ^2 r8 E+ \4 S/ h
#include <GRAPHICS.H>
7 A7 p/ f. ~, R1 r, I g& z#include <STDLIB.H>
3 f+ E( j! c. F4 c#include <STDIO.H>5 L9 e5 x! p! a0 i6 X6 o8 O
#include <CONIO.H>
. C" n# N: S2 J/ C4 W$ u7 |int main(void)
, l. F6 N7 q* D. \& {+ V{ 2 P" Y5 n$ a- U% ?2 v) [
/* request auto detection */
0 N/ P1 |( A$ k, b! j+ Gint gdriver = DETECT, gmode, errorcode; 1 ~, Y+ l# r# `! O' e
int left, top, right, bottom; . L8 s B) `" r4 V. T) b
/* initialize graphics and local variables */ 2 Y8 B) F$ N) R( z8 i5 N: W' M
initgraph(&gdriver, &gmode, ""); 
8 ~: @4 K0 w" U/* read result of initialization */
# l' q/ u. p' Z3 U2 D" P" {7 [errorcode = graphresult(); ( ^; G2 y. Y1 L% G4 T4 ^2 D
if (errorcode != grOk) /* an error occurred */
7 S E1 x: o2 r7 T{ ) A: g; z, [, u+ [# f
printf("Graphics error: %s\n", grapherrormsg(errorcode)); * ?2 [. Y8 m% N6 {' F
printf("Press any key to halt:");
6 O& u" ]6 e3 y' Jgetch(); ! ^4 j$ U& s$ m7 \/ K
exit(1); /* terminate with an error code */ 1 n' T% t7 C0 A8 n$ Q: G
} 
7 ?- c t, I% ~4 U3 Fleft = getmaxx() / 2 - 50; 6 L. X# d% U3 P! Y. g' P1 O0 R
top = getmaxy() / 2 - 50; % k. d: h8 r: [
right = getmaxx() / 2 + 50;
1 {9 W6 v% D* l- ^2 n+ S. K; I8 jbottom = getmaxy() / 2 + 50; 9 ~) i+ p+ Z* {: _7 U, H0 P
/* draw a rectangle */ 1 e* H* b& p; @% C8 V
rectangle(left,top,right,bottom); 
- P; l* A9 L' Z. [2 l/ [/* clean up */ ' F' U- X$ W. B0 \' h( D; H# P
getch(); . n- X. \; K. H4 L
closegraph(); & B+ s1 M( t1 |& L" W: f$ d2 q
return 0;
* B; N j9 c; e. k# H} / f7 l7 K. S0 m

! m% K# U9 i& I. D0 h. S: p/ l5 p2 W# @8 j
函数名: registerbgidriver / n- v4 x |$ J
功能: 登录已连接进来的图形驱动程序代码 6 c% a0 p, L: y. l1 j* p0 Q
用法: int registerbgidriver(void(*driver)(void)); 1 t! g j; D& N& R' P
程序例: 
 K" W4 K! Y) v% M/ K#include <GRAPHICS.H>5 l9 ]8 g6 l# B& {1 m- ^# C
#include <STDLIB.H> _$ I1 @( w: T
#include <STDIO.H>
3 t) z. a- {; l/ f#include <CONIO.H>
3 x% C/ Q9 Z8 P' D, Uint main(void) + d: Z. G4 L0 c+ I3 z6 H# q
{ : }3 ]2 M, d, m+ i$ a' R. l( {$ B. f
/* request auto detection */
$ T% `7 T! u/ [4 b/ v$ T- O! ]int gdriver = DETECT, gmode, errorcode; ( q# B6 q' d4 q0 g
/* register a driver that was added into graphics.lib */
' `- L% x6 f) u; `8 @) Werrorcode = registerbgidriver(EGAVGA_driver); 
% H% w0 w2 S* d" N7 @/* report any registration errors */
7 h6 s, O9 c' r8 D1 v" i% Kif (errorcode < 0) 9 V0 }' h' F0 a+ A
{ " ?0 u7 M& E5 p+ Q& Z O7 z
printf("Graphics error: %s\n", grapherrormsg(errorcode)); 8 K* v" l* o+ S1 ?1 A2 A- ]6 J4 j
printf("Press any key to halt:");
& Z Q4 t7 v0 ]* c5 [getch(); 1 I1 Q, e5 h$ Y; f, s& Y
exit(1); /* terminate with an error code */
0 @- P4 }) u( C- J9 p} 
$ F7 R3 u g8 y5 b& P/* initialize graphics and local variables */
8 @/ l" r( U0 a& j, D! dinitgraph(&gdriver, &gmode, ""); 3 O2 { ]( k* X/ ~; j( L
/* read result of initialization */ / W+ u2 s& Q& m
errorcode = graphresult(); 8 u% W* I, Y# d, \" e5 B
if (errorcode != grOk) /* an error occurred */
4 n" j! [0 z7 t/ e4 ?. f% M{
/ g3 B* H6 r* y- x2 G" O2 \# z' nprintf("Graphics error: %s\n", grapherrormsg(errorcode)); + j; w4 `$ F- E
printf("Press any key to halt:"); + s/ `7 E3 Y( _; \/ V- O o% Z
getch();
) Y+ t6 h0 ?! Y% sexit(1); /* terminate with an error code */
5 X W& z& Q3 K R& e2 `} 5 {9 L5 I0 G; [- {0 k% S) T
/* draw a line */
0 e- Z0 W( \/ _1 k: o* `line(0, 0, getmaxx(), getmaxy()); % M, T! j3 W' b) F& t5 p
/* clean up */
5 v! m- W3 B- Hgetch();
2 m, X+ a8 q1 I9 {8 Cclosegraph();
3 O" }, s3 a1 F7 k2 p, @return 0;
1 i3 `9 U+ w: d- @6 f- x' Z} ; F6 f U9 H+ I. P# F; S
" D$ `) \ {/ I( s/ N
+ k9 |9 ~, _" @; x' [
函数名: remove 
6 R5 w: I% l, s$ ?功能: 删除一个文件
 ~7 O6 \0 ~0 a# e用法: int remove(char *filename); # W8 E8 g# J. [" I
程序例: , ~9 w$ Z4 n1 R5 ~; a3 k
#include <STDIO.H> \" H% I1 d0 z% E% ~) x8 o' H
int main(void) 4 l% ?3 S( m2 \7 p5 N7 D. r3 k
{ 1 q1 ^' h5 O- `1 X% S0 [) c: R
char file[80]; ' s8 I. D4 l) e" q- P, `
/* prompt for file name to delete */ # G& H( w' c8 D$ |. v2 V5 l6 G! ?
printf("File to delete: ");
# ~0 @* A' j# k8 v3 L, xgets(file); + o% N2 V2 ]8 p
/* delete the file */ - U: m6 {! c, F0 y" Q
if (remove(file) == 0)
. s! ]6 e! n! ?+ `8 pprintf("Removed %s.\n",file); 0 C x8 W6 _9 k1 r
else 5 F x$ |8 d2 i' {7 L* h; s
perror("remove"); 6 @3 E& u3 u/ k3 a+ Y1 i
return 0; ! @1 ^% P* [. M Q
} 6 n( ]4 `& o# h
. [% C! c% J- ~8 l0 O5 d% s

. K7 v; n& @2 j函数名: rename 
0 N% i; w0 R6 B7 M: f5 i6 u* ]3 [功能: 重命名文件
! x" F6 \9 S- ~6 S用法: int rename(char *oldname, char *newname); # E, g f Y5 {; j4 ~2 L% j
程序例: 
" b5 Y7 _! t, o0 k7 Q, l#include <STDIO.H>
7 r- H4 _9 }, Z# q) I% qint main(void)
 V2 K5 }* R( w7 [" s4 |2 w+ ?{
6 x* F6 R7 w9 ]( \0 ?: `2 vchar oldname[80], newname[80]; 
6 z" R0 I( v8 O& {. [3 _9 ]/* prompt for file to rename and new name */
4 O+ P2 w( e+ vprintf("File to rename: ");
6 L; P- z/ L4 A* ^gets(oldname); . }" |8 ]! @ F Y5 ?* K C
printf("New name: "); 0 Z' J1 |/ l: x) }. W4 T
gets(newname); 
2 b' U. M+ B! V3 Y/ j/* Rename the file */
0 N- c, Q" H8 [/ ^0 Eif (rename(oldname, newname) == 0) 9 S/ Y% [6 y3 Z
printf("Renamed %s to %s.\n", oldname, newname);
/ i0 p* J2 P& x3 o$ I" |9 Lelse 9 M9 m7 s. [' F4 f+ ~+ [9 b8 S
perror("rename"); , m% F0 S0 ^3 }6 {" ]
return 0;
: U7 E1 o+ `$ s7 v; T& m4 T} t7 B8 y: @( u+ q! h: I

$ G8 g. Z( Y+ D4 w
: e3 f, Y# _1 n# B函数名: restorecrtmode 1 \$ j8 g0 v/ f/ A6 J7 _# ?
功能: 将屏幕模式恢复为先前的imitgraph设置
3 B0 ?# |; h) D# w5 P+ \. s用法: void far restorecrtmode(void); ( z2 j, h0 U$ d- X$ J
程序例: " _, z {1 \! O- ?8 }) y- ?4 k
#include <GRAPHICS.H>
. l- l ~8 V* b#include <STDLIB.H>
8 }1 }+ o4 F6 T3 X+ G3 t. Z1 [#include <STDIO.H>: a, X' Q5 Y; Y N" C
#include <CONIO.H>, s' j. y' y5 e
int main(void) 2 b% u; p1 b$ E2 }% c1 D1 o& c
{
) e; d( {) p/ l" _/* request auto detection */ $ _" v; Z9 c0 l3 u0 ?% v
int gdriver = DETECT, gmode, errorcode; + x* v4 o3 w2 f+ T# K* B
int x, y; 
7 v9 B! x4 i. p& A/* initialize graphics and local variables */ 3 T; C8 i4 x* C: Q4 l3 _
initgraph(&gdriver, &gmode, ""); ) l0 P) j, \& S. y2 I
/* read result of initialization */ 7 L8 M4 C8 R7 ^2 |
errorcode = graphresult(); % l2 ~- Z3 D' P0 T9 H3 ]5 X
if (errorcode != grOk) /* an error occurred */
; c5 h- I- T& ^5 X{ 0 g4 X- e" R5 G
printf("Graphics error: %s\n", grapherrormsg(errorcode));
% F( v$ q& X+ k+ u% n6 Y* T) ] {printf("Press any key to halt:");
/ Z* y1 }5 K- e+ cgetch();
, |. o& v4 w3 W9 }exit(1); /* terminate with an error code */ 2 \% ~- |: Y1 V2 n
} 0 Q: ]0 j$ u W- }2 `
x = getmaxx() / 2;
0 [) G+ R/ }) e P: E+ {y = getmaxy() / 2; + S$ c3 ? F; ~4 A. f7 J8 X% X
/* output a message */ 1 o4 ~( f. w J- h3 O
settextjustify(CENTER_TEXT, CENTER_TEXT); 1 r: y+ P+ }' \! ?
outtextxy(x, y, "Press any key to exit graphics:"); K! r9 f/ J6 a4 U# p
getch(); . p+ {+ n! Z3 ]% \2 p
/* restore system to text mode */ q8 Z; [+ h, [ y t6 Z! H* L
restorecrtmode(); + C" D0 T9 B, R
printf("We're now in text mode.\n");
" b- T7 {) N* S9 M$ O3 H1 zprintf("Press any key to return to graphics mode:");
0 _& o: G3 S$ X, ?; q. kgetch(); 
3 T% ~6 \9 J- H8 r, P" S/* return to graphics mode */ ( E0 x' H& I3 K
setgraphmode(getgraphmode()); : d/ z; p; D( f
/* output a message */ 1 q3 ^( H, c# e# ]# ?( u& f
settextjustify(CENTER_TEXT, CENTER_TEXT);
$ l* X/ v! ~/ l. V. {: |outtextxy(x, y, "We're back in graphics mode.");
) C* ~: q# C* g* H; D* w1 Houttextxy(x, y+textheight("W"), "Press any key to halt:"); ) _" n+ S% `% ?8 P
/* clean up */
+ |! A' I0 N1 R" Ygetch();
$ x- V% N5 @& [ y1 v7 w9 cclosegraph(); $ M, I4 t; n: N* Y
return 0; 7 q5 }# h3 j9 e3 _
} , m) t" [8 `* S" i5 d/ V+ p5 B2 v" U

$ A+ B7 Q& p# B8 `" b
3 `) \. C8 ^$ U函数名: rewind , _3 ~; N. K0 V* u3 W i: B
功能: 将文件指针重新指向一个流的开头
: x, }( a) e& a/ Z# f, H/ f用法: int rewind(FILE *stream); ! ]; q& k4 ?9 ?: W5 H
程序例: 2 C# T. Q2 E* l# v. w
#include <STDIO.H>
8 ^+ Z" @7 X3 o4 D$ f$ Y#include <DIR.H>1 z3 R' w/ F3 }' G! z
int main(void) ( d% Z$ Y- w1 g2 a# e3 R
{
/ n- N* ]! O) t- RFILE *fp; : Y P$ y1 a, X7 v) [" r9 {/ O
char *fname = "TXXXXXX", *newname, first; 6 V( K* R) L0 @& ?
newname = mktemp(fname);
% B( h% g; c3 }% u9 A7 O, [; U: g+ h5 efp = fopen(newname,"w+");
5 A ~) b4 s; p% nfprintf(fp,"abcdefghijklmnopqrstuvwxyz"); . I: A7 e# G, U
rewind(fp);
, G' O! l$ G$ T. ]5 ~+ s& Z9 Hfscanf(fp,"%c",&first); " Z, }) n* G$ v) u, D
printf("The first character is: %c\n",first);
/ ^$ k/ [/ A, P( Vfclose(fp);
$ @( f$ l( H% o% rremove(newname); % k0 A4 x7 x" O: e
return 0; 8 H: s6 h! y F% _9 M: ?3 @* f
} 6 Q! b$ ~* t0 ~! \; B: W

 D$ c/ d# y7 E$ G8 I
5 s* ^/ e5 R l* }/ a( l1 f" d函数名: rmdir $ u( A8 E8 }; h) F; J$ p
功能: 删除DOS文件目录
; _/ R! W( n( x% w( Y5 o用法: int rmdir(char *stream);
) s( f/ y: U8 @1 e程序例: # y0 W$ x- ?& n+ D9 r' i2 C! X
#include <STDIO.H>
 |7 z8 p; A( B2 X/ l& w2 I#include <CONIO.H>
% o: G$ Q { k# O \5 ?2 N#include <PROCESS.H>
. h2 _( e8 i; ~8 m+ R#include <DIR.H>
5 ^$ E3 \; ?, R A" e#define DIRNAME "testdir.$$$" 
) D: q4 M M) iint main(void)
$ |% g: A( K5 W {+ y; c9 N{ 3 B3 ~* B9 D8 r# t
int stat; & p3 L. l9 t5 s- O! y
stat = mkdir(DIRNAME);
. ^3 M- Z, Y ?if (!stat)
! j3 N; O( R# N2 F* p# x. \# h, rprintf("Directory created\n");
" |% W* E0 t* q0 yelse . w/ x( k6 |% a' r
{ + U6 ]$ Z# g8 h$ B1 z' I5 ?$ j
printf("Unable to create directory\n");
% |: j) \; I% l0 iexit(1); 5 X- i M* x/ ^6 q$ F6 @3 s4 n1 G
} 
/ O6 N& n- Z; J0 r9 a* zgetch();
. v7 p3 y6 G8 Nsystem("dir/p");
- L' h- f9 x- L1 J4 F) Xgetch(); 4 W6 ^& w8 B1 K' g
stat = rmdir(DIRNAME); 2 M2 X& O& `& t$ Q
if (!stat)
. [0 \. K; c* X9 Xprintf("\nDirectory deleted\n");
+ P& ^. k$ O+ {: K6 Delse 1 z* Y6 G6 o/ A* J% S6 s) ]
{ # H+ ^# m" B, W# |7 M) e A0 o
perror("\nUnable to delete directory\n");
5 y3 N: [7 @; q' w" Zexit(1);
# H c" O4 D( P- q4 P) m} 
6 P/ Y) j: ^* C+ M/ hreturn 0;
! m5 n, J' E$ ]0 F: [) E# ~: k I$ r}