数学建模社区-数学中国

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); . X1 j& Z0 M" A
/* restore previous dta */
! v8 {6 A; x- ^! z) T' `. N' Qsetdta(save_dta); & r y6 h/ u& I2 `$ H' T! m+ H4 b
return 0; 0 r, M3 [) W; C
} 
3 G% y* X4 Q/ e, @( b0 S. e4 g* ]' H+ ?, r9 u
函数名: randbwr 
* e, b7 u) v3 c L4 h# B1 d功能: 随机块写 0 m/ V( s+ X+ d- H) }
用法: int randbwr(struct fcp *fcbptr, int reccnt);
! p) n& p( x- X* v0 Y& y {4 p程序例: * J3 g8 l+ l, R4 V1 `* y1 Z1 B
#include <PROCESS.H>4 F& v* [( \/ i2 k: B
#include <STRING.H>
: |0 U; V7 x5 B) e#include <STDIO.H>
0 v, E8 H9 K& `9 p% I7 K% z( P& J#include <DOS.H>/ z$ W1 U& M" N: M2 S
int main(void)
! e& I. V7 H5 u/ N( N{ 2 _. I9 ^, N$ L* a% s% Q
char far *save_dta;
, a' |2 ]. n. \. o3 S) Q9 a# hchar line[80];
. H6 d3 C2 m: G2 o7 h6 gchar buffer[256] = "RANDBWR test!";
6 O: d) m# w& D' jstruct fcb blk; 1 l. p! i+ V T: `% q7 l7 S1 p
int result; ; Z& B, j; ]/ m2 _ j3 k' H2 g1 J% Z
/* get new file name from user */ 4 V0 Y+ |: L2 Q8 q: _" r
printf("Enter a file name to create (no path - ie. a:file.dat\n");
, H+ s1 Y4 g- O+ C1 |gets(line); , a" v8 C* l/ p8 N- K, x( u
/* parse the new file name to the dta */ - p6 L/ B, P7 [0 M7 m& _* h% F
parsfnm(line,&blk,1);
+ @, c& G2 j& S% Wprintf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name); 
6 Q% [: s/ v8 v5 F! d$ Z/* request DOS services to create file */ 4 m4 l1 q( H& n. j* {, E
if (bdosptr(0x16, &blk, 0) == -1) 3 Z2 b% r. S$ M# O: D
{ 0 S- n8 X6 q1 V# Y4 @& Q, ~" R
perror("Error creating file");
/ S# t1 ~# A7 H. O4 Gexit(1); 2 [9 z5 S3 @; ~8 ]5 f) z
} 5 E' c. j" u5 h
/* save old dta and set new dta */ 3 f1 B# U1 }. F" `* L6 ^- b
save_dta = getdta();
% y4 W* O: a1 ~8 V' c {/ hsetdta(buffer); 
: c9 W5 @* G6 z/* write new records */ ; \0 B# v a, A/ ^, o
blk.fcb_recsize = 256;
2 H1 n' C- q0 p8 ]: s# }' sblk.fcb_random = 0L;
' ?+ P. X3 A: d4 oresult = randbwr(&blk, 1); / c. w- L2 T; c, O
if (!result)
1 d: b6 h9 c v4 E% j0 Kprintf("Write OK\n"); 1 k$ r2 E) L' N$ k* m# L
else
. [9 e; A4 R4 ?# F0 n9 }{ + `7 y) C& j. p3 X' P0 L
perror("Disk error");
$ d4 a. C) [ d& v8 r6 V cexit(1); % g# k- T" j/ C$ r
} 
! A% W6 a: r( ]9 |9 z/* request DOS services to close the file */ 5 P) `# N: H* u* d1 I5 `
if (bdosptr(0x10, &blk, 0) == -1)
5 c9 c, i8 Z/ K K{ ) v, z v) H7 L9 |0 A6 g/ H( L# N
perror("Error closing file"); 9 l) F# l7 q6 a2 {1 i& V* G3 v' _
exit(1);
6 C1 g8 y% E! B$ u9 V* m} $ e* m: n. C D* F' x% m
/* reset the old dta */ 6 w* N0 n) S6 S0 I* \* y( {
setdta(save_dta); 1 e4 |5 M7 F5 ]6 O& z2 s1 v8 ^
return 0;
' h' {+ {' X' r7 a# b9 o. A* {}
- e5 g4 O) J, Z6 D8 e& T- q" R
# Y, N; s& l& I" a
) h3 ^- l& M" O1 P; }1 j函数名: random 2 j4 F) x! v1 n4 z( |+ F
功能: 随机数发生器 6 Y1 X8 H. a: V1 O/ p H
用法: int random(int num);
: k7 _# Z! C/ ?3 O; _; g7 ]程序例: 
% {# n0 h5 o$ _ k9 K3 d#include <STDLIB.H>9 R# j5 d+ [2 b1 [ G* h
#include <STDIO.H>
; S. q9 s. q) X' d0 `( y#include <TIME.H>
3 E, X9 {- n+ ]7 _/* prints a random number in the range 0 to 99 */
) \* R4 V+ ~5 ]7 o7 _: dint main(void)
( K6 V3 n4 w! u# t/ q7 K* x{ - g* J4 y8 u8 ]# }
randomize(); h6 K5 H( C0 C
printf("Random number in the 0-99 range: %d\n", random (100));
. |8 A% R$ @9 T9 J( rreturn 0;
" x3 i& S; V7 S}
8 V6 i3 P) _9 a: V' Z$ y& C' ]
5 L b) Y$ O% K9 N# \$ _$ K; K8 ?, H5 ]3 g2 x( O
函数名: randomize 
3 \ e* a& v b+ q功能: 初始化随机数发生器
 |6 g$ v, C, j0 N5 ~用法: void randomize(void); . w% U7 e2 Q* L2 v3 X
程序例: * u5 C0 g& n1 [4 P2 U* D- r/ P3 ?5 O
#include <STDLIB.H>/ V D/ I0 t3 z
#include <STDIO.H>
3 g3 k- k, Q; O6 N#include <TIME.H>3 ^' ?$ d' E! t" L7 w
int main(void)
: D' o4 i/ U- L6 C! d{
& ~/ o I& r# ^ m& ~/ c, C5 t. eint i; ! [0 M5 k: u" w! K
randomize();
: U5 I4 v4 n0 M# Lprintf("Ten random numbers from 0 to 99\n\n");
 [6 _0 W+ s- T( w; N1 kfor(i=0; i<10; i++)
. M( E; s' V$ ] h9 I8 R1 ~+ Cprintf("%d\n", rand() % 100); & z1 y" i8 C8 x% c' Y% T$ Q
return 0; - J8 h8 K% a0 Y. B3 Q
}

; p* j+ u0 V" V2 t3 x! A0 a
6 u$ o, M3 N* h. e函数名: read 
( C* a5 {) d2 a' L功能: 从文件中读
' q5 \4 u6 V H, t用法: int read(int handle, void *buf, int nbyte); # ~3 x6 K1 }2 m2 \7 Y
程序例: 
 b g0 @; Q3 { k7 u( W1 s#include <STDIO.H>
+ v5 g' @& C# _% u3 Q( q- H#include <IO.H>
9 g$ x' l! H& ~8 U# u" _#include <ALLOC.H>
6 E! a0 f+ m5 X8 m( I1 D: i# A) P#include <FCNTL.H>
3 h+ ^3 w- O% G& A( ^#include <PROCESS.H>/ h- E! q# H* R$ A# G" d
#include <SYS\STAT.H>
7 O6 J+ u x1 aint main(void) $ k& x' _* f7 b0 J, R2 ]3 T
{
5 a' t$ R+ q- l& J4 N( Dvoid *buf; s. w1 U5 [# M4 Y
int handle, bytes; 4 h1 ^6 v' }2 l i, E9 _3 E
buf = malloc(10); 5 a7 p# P; K5 w0 X
/* $ q" F" U' m. W) A5 m; H6 h% m% ]
Looks for a file in the current directory named TEST.$$$ and attempts
9 G; x& H. A" O( L9 g/ G0 f% Lto read 10 bytes from it. To use this example you should create the / o. }' L2 d' A4 H. B( g0 F
file TEST.$$$ ; ?( d& |7 V+ H6 }
*/ 8 A% l! t4 w7 b6 o, K/ E
if ((handle =
, j8 q& V5 R, Q; h4 \) c' qopen("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1)
 X+ c1 q0 W* f) ^, R! G4 }{
: K2 M$ v* T5 n7 }+ d5 M, Xprintf("Error Opening File\n");
6 X0 T3 E- u% ?7 B' K& U$ Q* fexit(1);
% Z" X) I% g. ?# C( n5 P9 J} 
# X2 B; x4 ]6 {9 qif ((bytes = read(handle, buf, 10)) == -1) {
* {* q& l' P+ X) r! L% `% \# tprintf("Read Failed.\n");
- d# w- W3 V0 a: U$ Q l8 j; Cexit(1); 5 @# b4 H7 Y4 Y9 n1 L9 q
} + A& b5 J! A0 ~; e; B+ i
else { & F4 \0 K) g! w; P( E
printf("Read: %d bytes read.\n", bytes); # d3 `6 c: w- f; G3 g \
} 4 |3 K3 z- i( Q& @
return 0;
( X# a4 g% b- X& c$ s, \} ; G* l( K- ?0 W: n& C

, n+ U! F0 t) f- V0 J. `7 [2 l+ _% v
函数名: realloc / T0 E0 H( C% x8 c- _1 c, M% b: G
功能: 重新分配主存 : i0 Y) \! A& H, ^3 L- O, K! N
用法: void *realloc(void *ptr, unsigned newsize); " `9 p3 ^$ w6 G2 u( C
程序例: " \" Q2 D1 j* E8 F
#include <STDIO.H>/ _2 t3 L: J" L, ]4 S1 [
#include <ALLOC.H>7 c9 D) w' U+ Q4 F+ d3 ]
#include <STRING.H>3 z2 B, }1 C* y/ A9 J6 r
int main(void) / E4 D" Z% U. W- E5 J- N
{ 4 e% L. \3 t: |+ d' }, }! \
char *str; # V5 j4 Y* v" }1 D7 c' c2 l* r
/* allocate memory for string */
4 `; p; ~5 v- I* G) S0 L5 k8 C7 \+ i: xstr = malloc(10); 
7 O$ Q1 n. u2 j+ ]8 o q/* copy "Hello" into string */ ' P: q1 b+ r3 f
strcpy(str, "Hello"); # l1 c% G+ Q9 `' N; S
printf("String is %s\n Address is %p\n", str, str); 9 @3 a- ~. N3 M' G* c
str = realloc(str, 20); 8 P6 ?. q' t" G: b2 a- ]
printf("String is %s\n New address is %p\n", str, str); 0 u5 h' y; C! ?8 r+ s: K
/* free memory */
, L, y$ d4 }! i1 I( Lfree(str); 
* x& F! g t, m7 a! y3 P( [return 0;
* G4 W% k! U3 \/ M* o( X$ ]) G' }}
, C2 Y7 G/ I- `; t2 G
' C- g- V2 }/ L# L0 x+ ?" ?( ^ E# H7 [, w/ S% ]3 G) F/ ]9 q7 c
函数名: rectangle 6 B( [( b) w% @5 s; A0 g8 z0 x" N
功能: 画一个矩形
" K% ?7 W, o: L2 [) f2 x8 z* q用法: void far rectangle(int left, int top, int right, int bottom); & I& n( {( G+ _$ W' n
程序例: 
6 Y8 v# |- V, x6 ^/ F#include <GRAPHICS.H>
- F$ @9 w8 k$ N$ i# T#include <STDLIB.H>9 b% o* S1 I9 G) w) [0 |
#include <STDIO.H>
5 L0 O! L' |! T8 _2 E8 p#include <CONIO.H>
$ o2 r3 B* Q7 W! Pint main(void) 3 p1 q9 Q4 V2 M. M" s j
{
6 `7 x2 G2 T( q5 Y/* request auto detection */
- \3 u) |3 O% Zint gdriver = DETECT, gmode, errorcode;
+ z4 Z' C# H4 U$ M% Z9 k8 uint left, top, right, bottom; {) k$ z% ^1 v, b3 F( D Y4 F* a
/* initialize graphics and local variables */ # R r& Z6 P/ A: g1 `
initgraph(&gdriver, &gmode, ""); 
8 S' X8 e2 T8 b2 z) `' e2 ^/* read result of initialization */
/ m+ E2 Q5 Y) h5 w7 R2 r2 V6 @errorcode = graphresult(); 2 l6 G$ e1 q/ p H) \
if (errorcode != grOk) /* an error occurred */ 4 H- m7 t8 ~+ C3 ]! r
{ 2 y7 C/ u! n; g+ e
printf("Graphics error: %s\n", grapherrormsg(errorcode)); ( c: W. s- j. m, P1 g
printf("Press any key to halt:"); $ U( K* C" v8 D' L* I# d2 {% q
getch();
- b, p8 H4 c* y* P6 @& Y3 Aexit(1); /* terminate with an error code */ $ o% d1 E& \2 j* y
} 
* n0 }3 J% }# T; Yleft = getmaxx() / 2 - 50; " e6 R% M S( x7 [
top = getmaxy() / 2 - 50;
1 Z7 C1 v/ T3 l( `. Gright = getmaxx() / 2 + 50; ; _' o& y* w/ @; w7 O" j
bottom = getmaxy() / 2 + 50; 
/ [ |9 F( ^: R, O9 l/ F/* draw a rectangle */
* C9 `( I& ?# \# Y1 X0 p$ N! Zrectangle(left,top,right,bottom); 
6 R! c9 R/ n: Y7 m. _) }/* clean up */ 3 ^. V. a9 N; x4 H* M4 a7 G
getch();
# x' h. T# @" ~# Q4 c) h1 ]closegraph();
- j. [7 b1 W7 z$ l. }% M: a! A/ Lreturn 0;
4 I o: c! D, \1 |! K! Y, M} 5 U* y) t; j/ \9 e5 X9 R" a; x

6 q) r! j A w; @. {
6 t( T* K' w6 g. Q3 [( M2 V0 y函数名: registerbgidriver 
6 f2 ^* o" U+ J. O0 g功能: 登录已连接进来的图形驱动程序代码
; [( M7 s; q) f2 A( r0 ?/ b用法: int registerbgidriver(void(*driver)(void));
* Y U0 U' g3 X% w1 X- w B* m程序例: $ ]* h9 S8 h6 T
#include <GRAPHICS.H>- i: A! m( s; _0 m H* q$ W
#include <STDLIB.H>
" ^; S8 ?- E9 h" v8 y2 `& m! {#include <STDIO.H>
' u9 C+ S0 c8 u0 x2 P* p#include <CONIO.H>4 a2 q4 I9 z( |. w! W% p
int main(void) 2 o6 y" ~+ n5 h4 H' }
{ & ~% T, B* B1 O" s1 A( K
/* request auto detection */ ) f: n Y/ N( o3 u. C2 C
int gdriver = DETECT, gmode, errorcode; 
" x& {7 x9 `6 ~/* register a driver that was added into graphics.lib */
0 |+ ^, H. D" j" D Serrorcode = registerbgidriver(EGAVGA_driver); + D1 |# c, C9 e; {& } v! X
/* report any registration errors */
1 }- V% z, {; m( b; ]- v& _if (errorcode < 0)
; [$ E" L2 B# o5 Z{ 9 L+ p1 G1 z, r, G* r/ H
printf("Graphics error: %s\n", grapherrormsg(errorcode));
. Y: v: C/ p6 ~" e m+ Rprintf("Press any key to halt:"); 8 R3 j% [. H/ s6 c( j7 {4 G
getch(); - s2 K: V: @9 |
exit(1); /* terminate with an error code */
; c: _ k/ d; v/ E ?} 1 ~' {0 g; l& [4 P! A* s
/* initialize graphics and local variables */ . Z; L. H7 o" ~. T6 s2 B% [8 s. J
initgraph(&gdriver, &gmode, ""); 
) d1 x5 J- o% z: X/ E1 B/* read result of initialization */
9 Z3 m+ m0 n R, ~- \errorcode = graphresult();
% C* @* D( R+ g3 i. o+ h' Oif (errorcode != grOk) /* an error occurred */
' g- {4 R) {; |* N# r$ z& R4 w{
" X3 a! S2 i; D0 c% d' yprintf("Graphics error: %s\n", grapherrormsg(errorcode)); ( B+ t: T8 R( N+ X$ b7 ]# f9 p( K8 c* I
printf("Press any key to halt:"); 4 j( m! i" G1 _9 P, H3 e
getch(); ( i1 R$ l1 J7 i( \, Y$ J% S; M
exit(1); /* terminate with an error code */
 K& l5 S' l8 W. Z} 4 @3 B2 p/ C* N2 ~! C: u
/* draw a line */
line(0, 0, getmaxx(), getmaxy()); 
+ s4 U) b. w" I% [, H5 h! N2 v/* clean up */
4 R1 b# B P t: k Dgetch();
; r) w8 Y' }' g$ u zclosegraph(); z( k9 f3 z7 Y( i4 m( k
return 0;
* e4 `/ F; R& u1 h3 t2 v} & T$ t4 Z; f0 z+ P1 r( n6 A
1 ~4 E8 }% D0 B, k/ @; V

0 j m. S9 h! Q3 s函数名: remove \# e% R* y# W
功能: 删除一个文件 / Q4 ^' L( o% C$ h. V7 q3 p6 W1 c1 a
用法: int remove(char *filename); y( a3 Q4 h: Z6 z; A+ h( q
程序例: 
' m5 h6 ]' ^# E+ j% b#include <STDIO.H>
/ w/ ?7 _" q7 hint main(void) $ ?8 h) }! V7 `! G3 v
{ 9 t8 o& y2 v! w7 c
char file[80]; 
; J! G8 p4 M3 z* v/* prompt for file name to delete */
 I; ~: |3 r1 o) [ t4 Zprintf("File to delete: "); : y3 h5 C4 L3 n0 z! }
gets(file); ; u' H+ ]1 J* O/ u* Z2 A: I3 ^0 Q. B
/* delete the file */
% K5 S* z3 {7 \2 G6 d1 G, d; |, tif (remove(file) == 0)
: e5 f# J9 E4 c2 ]printf("Removed %s.\n",file);
 a; H% l7 R6 ]' L: n6 f4 j7 lelse
. R* P' z3 ^3 a" @/ i+ z; K( bperror("remove"); 
% u& f2 r8 I' Dreturn 0; a5 _6 ^( u3 {# k
} ' r* Y! x) j8 {

* }8 H. G1 y- a3 ~3 E; o8 w* J6 C0 O( q4 h
函数名: rename 
& S& N) K9 Z: l3 L0 q% f3 j* ~功能: 重命名文件 9 b* `8 ] G. }+ A
用法: int rename(char *oldname, char *newname);
2 r( k, |, y7 H: M' j程序例: . M0 C( {4 A/ k/ j! t m4 s
#include <STDIO.H>
0 }7 c& i6 X; h1 I! mint main(void)
0 [8 _, ] A: B6 n9 @( D! b{ + `8 J7 E% o9 u2 p! t8 k& N
char oldname[80], newname[80]; * _/ w! A5 b& V$ I. y8 E
/* prompt for file to rename and new name */ $ R0 s3 V' f% S/ G- ^
printf("File to rename: ");
5 X* T9 Y& Q7 `4 ~. p! e7 Jgets(oldname);
9 R$ Q5 r: V5 O+ Q B& Aprintf("New name: ");
 i% p% c, z# v: Z8 Z& n) agets(newname); m/ c/ c2 h; z. i0 F0 d
/* Rename the file */
! ^( m/ k* Y" N+ W$ pif (rename(oldname, newname) == 0)
% Z' L: `' R% v6 Fprintf("Renamed %s to %s.\n", oldname, newname); * K5 O) F+ _+ G. V$ i
else b; Q2 ^5 C) k a9 H8 i! C
perror("rename"); 
( f9 Z/ q8 g N$ u: S/ treturn 0; 0 S4 w- A4 {$ S0 y+ U
} / F, x3 U' F. T9 u0 G

/ e& ?4 `8 h, `/ v, H( N: e4 Y* h, n* b {. N' r4 [
函数名: restorecrtmode 
 Q. {( l1 B' l功能: 将屏幕模式恢复为先前的imitgraph设置 ) _. Y) ?% X( J
用法: void far restorecrtmode(void);
 { C6 t( L" N6 E9 N程序例: 
- L# j. B5 T; h% i/ Z#include <GRAPHICS.H>9 U8 h4 e7 M, e
#include <STDLIB.H>& P- A0 V$ J# z# j; Q
#include <STDIO.H>
) ]( g2 [4 g) v( t4 _* z#include <CONIO.H>% x8 s! t; Y2 \# ?! v
int main(void)
% V+ z" u) D/ K, T! z{ 8 G E. ^7 _+ u* g H1 }
/* request auto detection */
9 }2 W1 `4 q9 ?int gdriver = DETECT, gmode, errorcode;
7 Y- D7 V' X8 N/ b. P9 ^$ yint x, y; 
7 J! q- L9 z. G) `- h" w/ s/* initialize graphics and local variables */
" i- L! |; C5 y* I* p, Minitgraph(&gdriver, &gmode, ""); 
+ a" F }# A% K- j3 {$ h. j/* read result of initialization */
/ R; Q6 t, Q. o- \* w8 g4 merrorcode = graphresult(); 4 ^ w+ e; @1 z$ a* F3 h- E
if (errorcode != grOk) /* an error occurred */
' Z, \6 n- V! u- P* F{
* `( d1 Y7 `1 t" h( d$ i# \( P0 w& yprintf("Graphics error: %s\n", grapherrormsg(errorcode)); # M1 P% s5 h: m Q, D
printf("Press any key to halt:"); \: [) V( _0 q- p
getch();
, _% D9 @7 Z1 Bexit(1); /* terminate with an error code */
: f" ^( E0 K* `+ K( i! L; q} 
1 I2 T2 x6 |. Kx = getmaxx() / 2;
1 E* {/ O; {4 S. J5 \y = getmaxy() / 2; / Y, x) i) w$ v! X
/* output a message */ : g7 m3 P& f% E& K" T: Q" ^
settextjustify(CENTER_TEXT, CENTER_TEXT);
# u _- w6 c* {outtextxy(x, y, "Press any key to exit graphics:");
( H/ k+ z/ f; E e3 @! Jgetch(); ) b3 e# [+ X9 Y& r7 T6 B) L8 ^5 _* m
/* restore system to text mode */ & `6 I/ a# E, C
restorecrtmode(); 0 ?- ~% ^3 j. P2 P8 Q
printf("We're now in text mode.\n");
+ O, S0 H3 S7 ]printf("Press any key to return to graphics mode:"); $ [- I1 N% W3 o. z! e4 } a6 W" @9 L( G
getch(); 
0 f. f( `1 h/ a( V* ]0 G/ ]/* return to graphics mode */
9 Y4 ]7 S0 @9 k! O G! Asetgraphmode(getgraphmode()); - Q4 @) V& H) |9 M. Q2 I8 j2 B: h
/* output a message */
" m( Y! d8 P) esettextjustify(CENTER_TEXT, CENTER_TEXT);
0 w* [- Y1 F7 h) u# j, \5 u: bouttextxy(x, y, "We're back in graphics mode.");
( [; T! e# H9 R" o+ U. H4 o7 fouttextxy(x, y+textheight("W"), "Press any key to halt:"); 
9 X8 G2 e* Q2 _! E0 p q7 v/* clean up */ / d9 E( |0 H* O$ e0 {* s- O8 n
getch();
, c) f; Z6 E% A' ^+ m0 B2 K, Rclosegraph(); ; e9 q5 W0 J+ B5 L# c: R: C
return 0;
1 C8 r+ t5 ?: [2 _! ~ x0 v}
8 O5 L1 s6 |4 O1 q2 t$ b
% r7 `( Z7 u$ W0 f% R' ?) @4 Q- F' i5 C( ]. E' I' a' K
函数名: rewind 
. E! w6 E6 o) q+ J8 ~功能: 将文件指针重新指向一个流的开头
" Z. p! v2 t$ ~# p用法: int rewind(FILE *stream); . ?5 ]. b6 [' }1 V- |) I
程序例: `: ^5 P3 ?7 p4 y6 {
#include <STDIO.H>6 N9 B ~$ s0 j% Y$ P& v
#include <DIR.H>" G3 T# G4 H# T
int main(void)
: J8 o* n! n% m6 S{ ! D/ r V$ V! j
FILE *fp;
) V$ I! P+ F7 p% zchar *fname = "TXXXXXX", *newname, first; 
2 _/ g8 l2 D" f* j% tnewname = mktemp(fname); : [% a* ]. }+ N: T+ Z4 U6 [ V
fp = fopen(newname,"w+"); ) M( b; F; P: y5 J: W
fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
* j0 J4 Q3 F+ {3 C* \& Erewind(fp); ; j: f5 M' x! `* Q
fscanf(fp,"%c",&first); 2 V5 o7 V( @& l
printf("The first character is: %c\n",first); , U6 f ?1 S% x, f1 R/ T* m
fclose(fp); * i8 ~5 f0 W# B6 U, V1 h3 {
remove(newname); 
/ {3 m8 E0 n' X2 k% jreturn 0;
, j' E( C; ]! _) r6 p$ j}
8 e5 `, F* |! N9 U8 ~4 t9 q+ a) t" g0 m6 [

: Z/ n) @" R, E. }' k函数名: rmdir 
3 i6 K# Z! Q) r0 r功能: 删除DOS文件目录
$ [/ ^9 W' d9 X- \3 U2 {8 A用法: int rmdir(char *stream); 0 t2 |' Q, d& [8 M! ]9 G" k) Y
程序例: 
1 p' M1 M8 {* O3 [- R$ _#include <STDIO.H>
, W2 E* a0 {6 ]" v7 s/ w+ h# j. ^9 _#include <CONIO.H>4 Q) |$ G: s" C1 a3 @: ]) o* U7 \
#include <PROCESS.H>: s& D4 i3 S' y6 ]7 T* c+ C9 G
#include <DIR.H>" H+ ]( z/ s) S0 \" O7 i1 ~1 K
#define DIRNAME "testdir.$$$" 
% |7 A# `, J, `( f. |9 z3 Nint main(void) + j/ F" T! j* E
{ 3 p) D- ?% ~& S4 C
int stat; 0 k) V$ ~$ W, O: Q
stat = mkdir(DIRNAME); + n% n% s9 ?; z$ i/ |8 u
if (!stat)
8 j' t1 k) V7 Y% Eprintf("Directory created\n"); 0 S) i5 P A6 h+ J$ ]+ N6 ^8 {
else
1 }) c( V7 G5 l! P" \: \$ _{
) \1 v7 B( D; ?; d- p+ t2 x$ \5 Iprintf("Unable to create directory\n"); 6 h9 @5 ?& m8 O+ r
exit(1);
3 u: F: s( y: E! c* w# s! n- D} " F" b+ Y9 C+ A$ r
getch(); " m4 b) B7 y, z3 G" P
system("dir/p"); ~8 b7 [7 r6 V+ H6 h
getch(); 
1 V- ~# p1 g- w. ystat = rmdir(DIRNAME); : L0 D( ~ |8 @6 M% b3 W
if (!stat) ! z/ [' K# }- P3 f+ `5 n
printf("\nDirectory deleted\n"); 7 u* Q8 z. r' v4 y% @
else
( m) B9 A3 F6 E% v{
* q& ?- x" J, q: d/ _perror("\nUnable to delete directory\n");
1 q* ]+ R+ S' l L9 ~exit(1);
) G+ t: o+ f7 G} 
) B) f( X$ g% e3 Preturn 0; : B7 f( Y# R9 H( Y
} 

欢迎光临数学建模社区-数学中国 (http://www.madio.net/) Powered by Discuz! X2.5