- cloud123
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函数名:abort
功 能:异常终止一个进程
函数与形参类型:
void abort(void);
程序例:
#include <stdio.h>
#include <stdlib.h> int main(void)
{
printf(Calling abort() );
abort();
return 0; /* This is never reached */
} 函数名:abs
功 能:计算整数num的值。返回整数num的绝对值
函数与参数类型:
int abs(num)
int num;
程序例:
#include <stdio.h>
#include <math.h> int main(void)
{
int number = -1234; printf(number: %d absolute value: %d , number, abs(number));
return 0;
} 函数名: absread, abswirte
功 能:绝对磁盘扇区读、写数据
函数与形参类型:
int absread(int drive, int nsects, int sectno, void *buffer);
int abswrite(int drive, int nsects, in tsectno, void *buffer);
程序例:
/* absread example */ #include <stdio.h>
#include <conio.h>
#include <process.h>
#include <dos.h> int main(void)
{
int i, strt, ch_out, sector;
char buf[512]; printf(Insert a diskette into drive A and press any key );
getch();
sector = 0;
if (absread(0, 1, sector, &buf) != 0)
{
perror(Disk problem);
exit(1);
}
printf(Read OK );
strt = 3;
for (i=0; i<80; i++)
{
ch_out = buf[strt+i];
putchar(ch_out);
}
printf( );
return(0);
} 函数名:access
功 能:确定文件的访问权限
函数与形参类型:
int access(const char *filename, int amode);
程序例:
#include <stdio.h>
#include <io.h> int file_exists(char *filename); int main(void)
{
printf(Does NOTEXIST.FIL exist: %s ,
file_exists(NOTEXISTS.FIL) ? YES : NO);
return 0;
} int file_exists(char *filename)
{
return (access(filename, 0) == 0);
} 函数名: acos
功 能:计算并返回arccos(x)值、要求-1<=X<=1
函数与形参类型:
double acos(x)
double x;
程序例:
#include <stdio.h>
#include <math.h> int main(void)
{
double result;
double x = 0.5; result = acos(x);
printf(The arc cosine of %lf is %lf , x, result);
return 0;
} 函数名:allocmem
功 能:分配DOS存储段
函数与形参类型:
int allocmem(unsigned size, unsigned *seg);
程序例:
#include <dos.h>
#include <alloc.h>
#include <stdio.h> int main(void)
{
unsigned int size, segp;
int stat; size = 64; /* (64 x 16) = 1024 bytes */
stat = allocmem(size, &segp);
if (stat == -1)
printf(Allocated memory at segment: %x , segp);
else
printf(Failed: maximum number of paragraphs available is %u ,
stat); return 0;
} 函数名:arc
功 能:画一弧线
函数与形参类型:
void far arc(int x, int y, int stangle, int endangle, int radius);
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 = 45, endangle = 135;
int radius = 100; /* initialize graphics and local variables */
initgraph(&gdriver, &gmode, ); /* read result of initialization */
errorcode = graphresult(); /* an error occurred */
if (errorcode != grOk)
{
printf(Graphics error: %s , 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 arc */
arc(midx, midy, stangle, endangle, radius); /* clean up */
getch();
closegraph();
return 0;
} 函数名: asctime
功 能:转换日期和时间为ASCII码
函数与形参类型:
char *asctime(const struct tm *tblock);
程序例:
#include <stdio.h>
#include <string.h>
#include <time.h> int main(void)
{
struct tm t;
char str[80]; /* sample loading of tm structure */ t. tm_sec = 1; /* Seconds */
t. tm_min = 30; /* Minutes */
t. tm_hour = 9; /* Hour */
t. tm_mday = 22; /* Day of the Month */
t. tm_mon = 11; /* Month */
t. tm_year = 56; /* Year - does not include century */
t. tm_wday = 4; /* Day of the week */
t. tm_yday = 0; /* Does not show in asctime */
t. tm_isdst = 0; /* Is Daylight SavTime; does not show in asctime */ /* converts structure to null terminated
string */ strcpy(str, asctime(&t));
printf(%s , str); return 0;
} 函数名::asin
功 能::计算并返回arcsin(x)值、要求-1<=X<=1
函数与形参类型:
double asin(x)
double x;
程序例:
#include <stdio.h>
#include <math.h> int main(void)
{
double result;
double x = 0.5; result = asin(x);
printf(The arc sin of %lf is %lf , x, result);
return(0);
} 函数名: assert
功 能:测试一个条件并可能使程序终止
函数与形参类型:
void assert(int test);
程序例:
#include <assert.h>
#include <stdio.h>
#include <stdlib.h> struct ITEM {
int key;
int value;
}; /* add item to list, make sure list is not null */
void additem(struct ITEM *itemptr) {
assert(itemptr != NULL);
/* add item to list */
} int main(void)
{
additem(NULL);
return 0;
} 函数名:atan
功 能:计算并返回arctan(x)的值
函数与形参类型:
double atan(double x);
程序例:
#include <stdio.h>
#include <math.h> int main(void)
{
double result;
double x = 0.5; result = atan(x);
printf(The arc tangent of %lf is %lf , x, result);
return(0);
} 函数名: atan2
功 能:计算并返回arctan(x/y)值
函数与形参类型:
double atan2(double y, double x);
程序例:
#include <stdio.h>
#include <math.h> int main(void)
{
double result;
double x = 90.0, y = 45.0; result = atan2(y, x);
printf(The arc tangent ratio of %lf is %lf , (y / x), result);
return 0;
} 函数名: atexit
功 能:注册终止函数
函数与形参类型:
int atexit(atexit_t func);
程序例:
#include <stdio.h>
#include <stdlib.h> void exit_fn1(void)
{
printf(Exit function #1 called );
} void exit_fn2(void)
{
printf(Exit function #2 called );
} int main(void)
{
/* post exit function #1 */
atexit(exit_fn1);
/* post exit function #2 */
atexit(exit_fn2);
return 0;
} 函数名: atof
功 能:把str指向的ASCⅡ字符串转换成一个double型整数返回双精度的结果
函数与形参类型:
double atof(str)
char*str;
程序例:
#include <stdlib.h>
#include <stdio.h> int main(void)
{
float f;
char *str = 12345.67; f = atof(str);
printf(string = %s float = %f , str, f);
return 0;
} 函数名:atoi
功 能:
把str指向的ASCⅡz字符串转换成一个整数。返回整数结果
函数与参数类型:
double atoi(str )
char *str;
程序例:
#include <stdlib.h>
#include <stdio.h> int main(void)
{
int n;
char *str = 12345.67; n = atoi(str);
printf(string = %s integer = %d , str, n);
return 0;
} 函数名:atol
功 能:
把字符串转换成长整型数 。返回长整数结果
函数与参数类型:
long atol(str )
char *str;
程序例:
#include <stdlib.h>
#include <stdio.h> int main(void)
{
long l;
char *str = 98765432; l = atol(lstr);
printf(string = %s integer = %ld , str, l);
return(0);
} 函数名:mkdir
功 能:建立一个目录
用 法:
int mkdir(char *pathname);
程序例:
#include <stdio.h>
#include <conio.h>
#include <process.h>
#include <dir.h>
int main(void)
{
int status;
clrscr();
status = mkdir(asdfjklm);
(!status) ? (printf(Directory created )) :
(printf(Unable to create directory ));
getch();
system(dir);
getch();
status = rmdir(asdfjklm);
(!status) ? (printf(Directory deleted )) :
(perror(Unable to delete directory));
return 0;
} 函数名: mktemp
功 能:建立唯一的文件名
用 法:
char *mktemp(char *template);
程序例:
#include <dir.h>
#include <stdio.h>
int main(void)
{
/* fname defines the template for the
temporary file. */
char *fname = TXXXXXX, *ptr;
ptr = mktemp(fname);
printf(%s ,ptr);
return 0;
} 函数名: MK_FP
功 能:设置一个远指针
用 法:
void far *MK_FP(unsigned seg, unsigned off);
程序例:
#include <dos.h>
#include <graphics.h>
int main(void)
{
int gd, gm, i;
unsigned int far *screen;
detectgraph(&gd, &gm);
if (gd == HERCMONO)
screen = MK_FP(0xB000, 0);
else
screen = MK_FP(0xB800, 0);
for (i=0; i<26; i++)
screen[i] = 0x0700 + ("a" + i);
return 0;
} 函数名: modf
功 能:把数分为整数和尾数
用 法:
double modf(double value, double *iptr);
程序例:
#include <math.h>
#include <stdio.h>
int main(void)
{
double fraction, integer;
double number = 100000.567;
fraction = modf(number, &integer);
printf(The whole and fractional parts of %lf are %lf and %lf ,
number, integer, fraction);
return 0;
} 函数名: movedata
功 能:拷贝字节
用 法:
void movedata(int segsrc, int offsrc, int segdest,
int offdest, unsigned numbytes);
程序例:
#include <mem.h>
#define MONO_BASE 0xB000
/* saves the contents of the monochrome screen in buffer */
void save_mono_screen(char near *buffer)
{
movedata(MONO_BASE, 0, _DS, (unsigned)buffer, 80*25*2);
}
int main(void)
{
char buf[80*25*2];
save_mono_screen(buf);
} 函数名: moverel
功 能:将当前位置(CP)移动一相对距离
用 法:
void far moverel(int dx, int dy);
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;
char msg[80];
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, );
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf(Graphics error: %s , grapherrormsg(errorcode));
printf(Press any key to halt:);
getch();
exit(1); /* terminate with an error code */
}
/* move the C.P. to location (20, 30) */
moveto(20, 30);
/* plot a pixel at the C.P. */
putpixel(getx(), gety(), getmaxcolor());
/* create and output a message at (20, 30) */
sprintf(msg, (%d, %d), getx(), gety());
outtextxy(20, 30, msg);
/* move to a point a relative distance */
/* away from the current value of C.P. */
moverel(100, 100);
/* plot a pixel at the C.P. */
putpixel(getx(), gety(), getmaxcolor());
/* create and output a message at C.P. */
sprintf(msg, (%d, %d), getx(), gety());
outtext(msg);
/* clean up */
getch();
closegraph();
return 0;
} 函数名: movetext
功 能:将屏幕文本从一个矩形区域拷贝到另一个矩形区域
用 法:
int movetext(int left, int top, int right, int bottom,
int newleft, int newtop);
程序例:
#include <conio.h>
#include <string.h>
int main(void)
{
char *str = This is a test string;
clrscr();
cputs(str);
getch();
movetext(1, 1, strlen(str), 2, 10, 10);
getch();
return 0;
} 函数名: moveto
功 能:将CP移到(x, y)
用 法:
void far moveto(int x, int y);
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;
char msg[80];
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, );
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf(Graphics error: %s , grapherrormsg(errorcode));
printf(Press any key to halt:);
getch();
exit(1); /* terminate with an error code */
}
/* move the C.P. to location (20, 30) */
moveto(20, 30);
/* plot a pixel at the C.P. */
putpixel(getx(), gety(), getmaxcolor());
/* create and output a message at (20, 30) */
sprintf(msg, (%d, %d), getx(), gety());
outtextxy(20, 30, msg);
/* move to (100, 100) */
moveto(100, 100);
/* plot a pixel at the C.P. */
putpixel(getx(), gety(), getmaxcolor());
/* create and output a message at C.P. */
sprintf(msg, (%d, %d), getx(), gety());
outtext(msg);
/* clean up */
getch();
closegraph();
return 0;
} 函数名: movemem
功 能:移动一块字节
用 法:
void movemem(void *source, void *destin, unsigned len);
程序例:
#include <mem.h>
#include <alloc.h>
#include <stdio.h>
#include <string.h>
int main(void)
{
char *source = Borland International;
char *destination;
int length;
length = strlen(source);
destination = malloc(length + 1);
movmem(source,destination,length);
printf(%s ,destination);
return 0;
} 函数名: normvideo
功 能:选择正常亮度字符
用 法:
void normvideo(void);
程序例:
#include <conio.h>
int main(void)
{
normvideo();
cprintf(NORMAL Intensity Text );
return 0;
} 函数名: nosound
功 能:关闭PC扬声器
用 法:
void nosound(void);
程序例:
/* Emits a 7-Hz tone for 10 seconds.
Tru