函数大全(e开头)

韩冰发表于 2004-10-4 03:01

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("Press 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); 
printf("About to exec child with arg1 arg2 ...\n");
execv("CHILD.EXE", argv); 
perror("exec error"); 
exit(1);
}


函数名: exit 
功能: 终止程序
用法: void exit(int status);
程序例: 
#include <STDLIB.H>
#include <CONIO.H>
#include <STDIO.H>
int main(void)
{
int status; 
printf("Enter either 1 or 2\n");
status = getch();
/* Sets DOS errorlevel */
exit(status - '0'); 
/* Note: this line is never reached */
return 0;
}


函数名: exp 
功能: 指数函数
用法: double exp(double x);
程序例: 
#include <STDIO.H>
#include <MATH.H>
int main(void)
{
double result;
double x = 4.0; 
result = exp(x);
printf("'e' raised to the power \
of %lf (e ^ %lf) = %lf\n",
x, x, result); 
return 0;
}

韩冰发表于 2004-10-4 03:02

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("Press 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);
printf("Press 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; /* 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 = 20; /* 1st vertext */
poly = maxy / 2; poly = maxx - 20; /* 2nd */
poly = 20; poly = maxx - 50; /* 3rd */
poly = maxy - 20; poly = maxx / 2; /* 4th */
poly = maxy / 2;
/*
drawpoly doesn't automatically close
the polygon, so we close it.
*/
poly = poly;
poly = poly; /* 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;
}

页: [1]

数学建模社区-数学中国's Archiver

函数大全(e开头)