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函数大全(e开头)

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韩冰

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电梯直达

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发表于 2004-10-4 03:01 |只看该作者 |倒序浏览

|招呼Ta 关注Ta

<

align=center>函数大全(e开头)


<

>函数名: ecvt 
功能: 把一个浮点数转换为字符串
用法: char ecvt(double value, int ndigit, int *decpt, int *sign);
程序例: 
<

>#include <STDLIB.H>
#include <STDIO.H>
#include <CONIO.H>
<

>int main(void)
{
char *string;
double value;
int dec, sign;
int ndig = 10; 
<

>clrscr();
value = 9.876;
string = ecvt(value, ndig, &dec, &sign);
printf("string = %s dec = %d \
sign = %d\n", string, dec, sign); 
<

>value = -123.45;
ndig= 15;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d sign = %d\n",
string, dec, sign);

<

>value = 0.6789e5; /* scientific
notation */
ndig = 5;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d\
sign = %d\n", string, dec, sign); 
<

>return 0;
} 


<

>函数名: ellipse 
功能: 画一椭圆
用法: void far ellipse(int x, int y, int stangle, int endangle,
int xradius, int yradius);
程序例: 
<

>#include <GRAPHICS.H>
#include <STDLIB.H>
#include <STDIO.H>
#include <CONIO.H>
<

>int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int midx, midy;
int stangle = 0, endangle = 360;
int xradius = 100, yradius = 50; 
<

>/* initialize graphics, local variables */
initgraph(&gdriver, &gmode, ""); 
<

>/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk)
/* an error occurred */
{
printf("Graphics error: %s\n",
grapherrormsg(errorcode));
printf("

ress any key to halt:");
getch();
exit(1);
/* terminate with an error code */
} 
<

>midx = getmaxx() / 2;
midy = getmaxy() / 2;
setcolor(getmaxcolor()); 
<

>/* draw ellipse */
ellipse(midx, midy, stangle, endangle,
xradius, yradius); 
<

>/* clean up */
getch();
closegraph();
return 0;
} 


<

>函数名: enable 
功能: 开放硬件中断
用法: void enable(void);
程序例: 
<

>/* ** NOTE:
This is an interrupt service routine. You can NOT compile this program
with Test Stack Overflow turned on and get an executable file which will
operate correctly.
*/ 
<

>#include <STDIO.H>
#include <DOS.H>
#include <CONIO.H>
<

>/* The clock tick interrupt */
#define INTR 0X1C 
<

>void interrupt ( *oldhandler)(void); 
<

>int count=0; 
<

>void interrupt handler(void)
{
/*
disable interrupts during the handling of the interrupt
*/
disable();
/* increase the global counter */
count++;
/*
re enable interrupts at the end of the handler
*/
enable();
/* call the old routine */
oldhandler();
} 
<

>int main(void)
{
/* save the old interrupt vector */
oldhandler = getvect(INTR); 
<

>/* install the new interrupt handler */
setvect(INTR, handler); 
<

>/* loop until the counter exceeds 20 */
while (count < 20)
printf("count is %d\n",count); 
<

>/* reset the old interrupt handler */
setvect(INTR, oldhandler); 
<

>return 0;
} 


<

>函数名: eof 
功能: 检测文件结束
用法: int eof(int *handle);
程序例: 
#include <SYS\STAT.H>
#include <STRING.H>
#include <STDIO.H>
#include <FCNTL.H>
#include <IO.H>
int main(void)
{
int handle;
char msg[] = "This is a test";
char ch; 
/* create a file */
handle = open("DUMMY.FIL",
O_CREAT | O_RDWR,
S_IREAD | S_IWRITE); 
/* write some data to the file */
write(handle, msg, strlen(msg)); 
/* seek to the beginning of the file */
lseek(handle, 0L, SEEK_SET); 
/*
reads chars from the file until hit EOF
*/
do
{
read(handle, &ch, 1);
printf("%c", ch);
} while (!eof(handle)); 
close(handle);
return 0;
}


函数名: exec... 
功能: 装入并运行其它程序的函数
用法: int execl(char *pathname, char *arg0, arg1, ..., argn, NULL);
int execle(char *pathname, char *arg0, arg1, ..., argn, NULL,
char *envp[]);
int execlp(char *pathname, char *arg0, arg1, .., NULL);
int execple(char *pathname, char *arg0, arg1, ..., NULL,
char *envp[]);
int execv(char *pathname, char *argv[]);
int execve(char *pathname, char *argv[], char *envp[]);
int execvp(char *pathname, char *argv[]);
int execvpe(char *pathname, char *argv[], char *envp[]);
程序例: 
/* execv example */
#include <PROCESS.H>
#include <STDIO.H>
#include <ERRNO.H>
void main(int argc, char *argv[])
{
int i; 
printf("Command line arguments:\n");
for (i=0; i<ARGC; printf("[%2d] : %s\n", i, argv); 
) i+ d9 B, @4 K( Z# Pprintf("About to exec child with arg1 arg2 ...\n"); / i" W0 R6 g( S9 I/ N( F3 |
execv("CHILD.EXE", argv); 
; h, G9 O- X: [+ gperror("exec error"); ' x$ n: o' u' _4 G0 L4 _3 ]
exit(1);
* G1 A: a0 H+ ~; b} l: U* B; ~9 e' F5 c6 X* }5 P
2 B+ ~+ }' I- E" W5 A/ e

. Z$ O2 G8 ^" b3 f j函数名: exit 5 i% J) p" ?2 a
功能: 终止程序 & [2 m5 _7 E; }1 l3 P4 i
用法: void exit(int status);
+ N# \# z9 Z: ?7 _程序例: - W4 F- J& n* B! n; e7 M- C
#include <STDLIB.H>
5 B( u+ |* Z5 W' L- Z: K" ?# \#include <CONIO.H>
% T" a8 y6 H8 z4 F! @# A3 y#include <STDIO.H>
% |7 `6 x5 P. x- {: z; m( gint main(void)
4 ~% M. Q4 A$ n' S* t, b{
( O) l, f- y; N% T9 T3 `% M% Tint status; 
5 }( A; w4 V' t8 A& oprintf("Enter either 1 or 2\n");
3 P: }/ i) B: J: @/ p9 @% zstatus = getch(); 2 `6 \4 K! S; k3 v. E7 a6 ]4 z
/* Sets DOS errorlevel */
) H: Q$ R, `# G6 X) h( jexit(status - '0'); 
5 L# d7 v+ U3 `: i/* Note: this line is never reached */
% V* j( f/ k1 D3 j$ r" m) Rreturn 0;
7 s2 {. j" _) q( N& \ j}
" g" P) O6 V X0 F
# k" G9 ~3 _+ ?* V8 ~3 ?5 r7 t$ g
. K2 f5 y8 E8 K9 e函数名: exp : g7 u1 L' g8 j; h: v
功能: 指数函数
( q( }6 {$ k' y, ]# A: W用法: double exp(double x);
$ e' p; I7 b5 k( p. W. U程序例: ' i8 h6 }/ L# k1 g) H) h3 Q
#include <STDIO.H>) k: H" @7 A5 d! `, A0 b
#include <MATH.H>+ @& I' K5 P, A4 }( V4 L: t
int main(void) 3 g/ _% T5 t4 x- l
{
2 N2 u/ P5 J+ h$ ddouble result; . |2 b# O& Z# u( M5 P
double x = 4.0; 
7 a" x% C7 `- k# ?4 l: n0 Gresult = exp(x); " D% p( v+ ]$ X z6 G7 _
printf("'e' raised to the power \
$ s# t) e6 N9 A% A+ U- G7 vof %lf (e ^ %lf) = %lf\n",
9 V+ |- Q9 _. n; e9 t: zx, x, result); ; z8 E1 v/ E, I- o) c+ D/ A2 C9 r
return 0; 7 x9 }' T9 t' T. i; u
}
9 _" j" V( I. p& p9 v

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韩冰

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2^#

发表于 2004-10-4 03:02 |只看该作者 |招呼Ta 关注Ta

<

align=center>函数大全(d开头)

<

>函数名: delay 
功能: 将程序的执行暂停一段时间(毫秒)
用法: void delay(unsigned milliseconds);
程序例:
/* Emits a 440-Hz tone for 500 milliseconds */
#include <DOS.H><

>int main(void)
{
sound(440);
delay(500);
nosound(); <

>return 0;
}

<

>函数名: delline 
功能: 在文本窗口中删去一行
用法: void delline(void);
程序例: <

>#include <CONIO.H><

>int main(void)
{
clrscr();
cprintf("The function DELLINE deletes \
the line containing the\r\n");
cprintf("cursor and moves all lines \
below it one line up.\r\n");
cprintf("DELLINE operates within the \
currently active text\r\n");
cprintf("window. Press any key to \
continue . . .");
gotoxy(1,2); /* Move the cursor to the
second line and first column */
getch(); <

>delline();
getch(); <

>return 0;
} 
<

>函数名: detectgraph 
功能: 通过检测硬件确定图形驱动程序和模式
用法: void far detectgraph(int far *graphdriver, int far *graphmode);
程序例: <

>#include <GRAPHICS.H>
#include <STDLIB.H>
#include <STDIO.H>
#include <CONIO.H><

>/* names of the various cards supported */
char *dname[] = { "requests detection",
"a CGA",
"an MCGA",
"an EGA",
"a 64K EGA",
"a monochrome EGA",
"an IBM 8514",
"a Hercules monochrome",
"an AT&T 6300 PC",
"a VGA",
"an IBM 3270 PC"
}; <

>int main(void)
{
/* returns detected hardware info. */
int gdriver, gmode, errorcode; <

>/* detect graphics hardware available */
detectgraph(&gdriver, &gmode); <

>/* read result of detectgraph call */
errorcode = graphresult();
if (errorcode != grOk) /* an error
occurred */
{
printf("Graphics error: %s\n", \
grapherrormsg(errorcode));
printf("

ress any key to halt:");
getch();
exit(1); /* terminate with an error
code */
} <

>/* display the information detected */
clrscr();
printf("You have %s video display \
card.\n", dname[gdriver]);
printf("

ress any key to halt:");
getch();
return 0;
} 

<

>函数名: difftime 
功能: 计算两个时刻之间的时间差
用法: double difftime(time_t time2, time_t time1);
程序例: <

>#include <TIME.H>
#include <STDIO.H>
#include <DOS.H>
#include <CONIO.H><

>int main(void)
{
time_t first, second; <

>clrscr();
first = time(NULL); /* Gets system
time */
delay(2000); /* Waits 2 secs */
second = time(NULL); /* Gets system time
again */ <

>printf("The difference is: %f \
seconds\n",difftime(second,first));
getch(); <

>return 0;
}

<

>函数名: disable 
功能: 屏蔽中断
用法: void disable(void);
程序例: <

>/***NOTE: This is an interrupt service
routine. You cannot compile this program
with Test Stack Overflow turned on and
get an executable file that operates
correctly. */ <

>#include <STDIO.H>
#include <DOS.H>
#include <CONIO.H><

>#define INTR 0X1C /* The clock tick
interrupt */ <

>void interrupt ( *oldhandler)(void); <

>int count=0; void interrupt handler(void)
{
/* disable interrupts during the handling of
the interrupt */
disable();
/* increase the global counter */
count++;
/* reenable interrupts at the end of the
handler */
enable();
/* call the old routine */
oldhandler();
} int main(void)
{
/* save the old interrupt vector */
oldhandler = getvect(INTR); /* install the new interrupt handler */
setvect(INTR, handler); /* loop until the counter exceeds 20 */
while (count < 20)
printf("count is %d\n",count); /* reset the old interrupt handler */
setvect(INTR, oldhandler); return 0;
} 函数名: div 
功能: 将两个整数相除, 返回商和余数
用法: div_t (int number, int denom);
程序例: #include <STDLIB.H>
#include <STDIO.H>div_t x; int main(void)
{
x = div(10,3);
printf("10 div 3 = %d remainder %d\n", x.quot, x.rem); return 0;
}

函数名: dosexterr 
功能: 获取扩展DOS错误信息
用法: int dosexterr(struct DOSERR *dblkp);
程序例: #include <STDIO.H>
#include <DOS.H>int main(void)
{
FILE *fp;
struct DOSERROR info; fp = fopen("perror.dat","r");
if (!fp) perror("Unable to open file for
reading");
dosexterr(&info); printf("Extended DOS error \
information:\n");
printf(" Extended error: \
%d\n",info.exterror);
printf(" Class: \
%x\n",info.class);
printf(" Action: \
%x\n",info.action);
printf(" Error Locus: \
%x\n",info.locus); return 0;
} 

函数名: dostounix 
功能: 转换日期和时间为UNIX时间格式
用法: long dostounix(struct date *dateptr, struct time *timeptr);
程序例: #include <TIME.H>
#include <STDDEF.H>
#include <DOS.H>
#include <STDIO.H>int main(void)
{
time_t t;
struct time d_time;
struct date d_date;
struct tm *local; getdate(&d_date);
gettime(&d_time); t = dostounix(&d_date, &d_time);
local = localtime(&t);
printf("Time and Date: %s\n", \
asctime(local)); return 0;
} 

函数名: drawpoly 
功能: 画多边形
用法: void far drawpoly(int numpoints, int far *polypoints);
程序例: #include <GRAPHICS.H>
#include <STDLIB.H>
#include <STDIO.H>
#include <CONIO.H>int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int maxx, maxy; /* our polygon array */
int poly[10]; /* initialize graphics and local
variables */
initgraph(&gdriver, &gmode, ""); /* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk)
/* an error occurred */
{
printf("Graphics error: %s\n", \
grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
/* terminate with an error code */
exit(1);
} maxx = getmaxx();
maxy = getmaxy(); poly[0] = 20; /* 1st vertext */
poly[1] = maxy / 2; poly[2] = maxx - 20; /* 2nd */
poly[3] = 20; poly[4] = maxx - 50; /* 3rd */
poly[5] = maxy - 20; poly[6] = maxx / 2; /* 4th */
poly[7] = maxy / 2;
/*
drawpoly doesn't automatically close
the polygon, so we close it.
*/
poly[8] = poly[0];
poly[9] = poly[1]; /* draw the polygon */
drawpoly(5, poly); /* clean up */
getch();
closegraph();
return 0;
}

函数名: dup 
功能: 复制一个文件句柄
用法: int dup(int handle);
程序例: #include <STRING.H>
#include <STDIO.H>
#include <CONIO.H>
#include <IO.H>void flush(FILE *stream); int main(void)
{
FILE *fp;
char msg[] = "This is a test"; /* create a file */
fp = fopen("DUMMY.FIL", "w"); /* write some data to the file */
fwrite(msg, strlen(msg), 1, fp); clrscr();
printf("Press any key to flush \
DUMMY.FIL:");
getch(); /* flush the data to DUMMY.FIL without
closing it */
flush(fp); printf("\nFile was flushed, Press any \
key to quit:");
getch();
return 0;
} void flush(FILE *stream)
{
int duphandle; /* flush TC's internal buffer */
fflush(stream); /* make a duplicate file handle */
duphandle = dup(fileno(stream)); /* close the duplicate handle to flush the
DOS buffer */
close(duphandle);
}

函数名: dup2 
功能: 复制文件句柄
用法: int dup2(int oldhandle, int newhandle);
程序例: #include <SYS\STAT.H>
#include <STRING.H>
#include <FCNTL.H>
#include <IO.H>int main(void)
{
#define STDOUT 1 int nul, oldstdout;
char msg[] = "This is a test"; /* create a file */
nul = open("DUMMY.FIL", O_CREAT | O_RDWR,
S_IREAD | S_IWRITE); /* create a duplicate handle for standard
output */
oldstdout = dup(STDOUT);
/*
redirect standard output to DUMMY.FIL
by duplicating the file handle onto the
file handle for standard output.
*/
dup2(nul, STDOUT); /* close the handle for DUMMY.FIL */
close(nul); /* will be redirected into DUMMY.FIL */
write(STDOUT, msg, strlen(msg)); /* restore original standard output
handle */
dup2(oldstdout, STDOUT); /* close duplicate handle for STDOUT */
close(oldstdout); return 0;
}