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<HTML><HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=gb2312"> <META NAME="Author" CONTENT="wdg"> <META NAME="GENERATOR" CONTENT="Mozilla/4.03 [en] (Win95; I) [Netscape]"> <TITLE>fa</TITLE></HEAD><BODY> <P>函数名: abort<BR>功 能: 异常终止一个进程<BR>用 法: void abort(void);<BR>程序例:<BR>#include <stdio.h><BR>#include <stdlib.h><P>int main(void)<BR>{<BR> printf("Calling abort()\n");<BR> abort();<BR> return 0; /* This is never reached */<BR>}<BR> <BR> <P>函数名: abs<BR>功 能: 求整数的绝对值<BR>用 法: int abs(int i);<BR>程序例:<BR>#include <stdio.h><BR>#include <math.h><P>int main(void)<BR>{<BR> int number = -1234;<P> printf("number: %d absolute value: %d\n", number, abs(number));<BR> return 0;<BR>}<BR> <BR> <P>函数名: absread, abswirte<BR>功 能: 绝对磁盘扇区读、写数据<BR>用 法: int absread(int drive, int nsects, int sectno, void *buffer);<BR> int abswrite(int drive, int nsects, in tsectno, void *buffer);<BR>程序例:<BR>/* absread example */<P>#include <stdio.h><BR>#include <conio.h><BR>#include <process.h><BR>#include <dos.h><P>int main(void)<BR>{<BR> int i, strt, ch_out, sector;<BR> char buf[512];<P> printf("Insert a diskette into drive A and press any key\n");<BR> getch();<BR> sector = 0;<BR> if (absread(0, 1, sector, &buf) != 0)<BR> {<BR> perror("Disk problem");<BR> exit(1);<BR> }<BR> printf("Read OK\n");<BR> strt = 3;<BR> for (i=0; i<80; i++)<BR> {<BR> ch_out = buf[strt+i];<BR> putchar(ch_out);<BR> }<BR> printf("\n");<BR> return(0);<BR>}<BR> <BR> <BR> <P>函数名: access<BR>功 能: 确定文件的访问权限<BR>用 法: int access(const char *filename, int amode);<BR>程序例:<BR>#include <stdio.h><BR>#include <io.h><P>int file_exists(char *filename);<P>int main(void)<BR>{<BR> printf("Does NOTEXIST.FIL exist: %s\n",<BR> file_exists("NOTEXISTS.FIL") ? "YES" : "NO");<BR> return 0;<BR>}<P>int file_exists(char *filename)<BR>{<BR> return (access(filename, 0) == 0);<BR>}<BR> <P>函数名: acos<BR>功 能: 反余弦函数<BR>用 法: double acos(double x);<BR>程序例:<BR>#include <stdio.h><BR>#include <math.h><P>int main(void)<BR>{<BR> double result;<BR> double x = 0.5;<P> result = acos(x);<BR> printf("The arc cosine of %lf is %lf\n", x, result);<BR> return 0;<BR>}<BR> <BR> <P>函数名: allocmem<BR>功 能: 分配DOS存储段<BR>用 法: int allocmem(unsigned size, unsigned *seg);<BR>程序例:<BR>#include <dos.h><BR>#include <alloc.h><BR>#include <stdio.h><P>int main(void)<BR>{<BR> unsigned int size, segp;<BR> int stat;<P> size = 64; /* (64 x 16) = 1024 bytes */<BR> stat = allocmem(size, &segp);<BR> if (stat == -1)<BR> printf("Allocated memory at segment: %x\n",segp);<BR> else<BR> printf("Failed: maximum number of paragraphsavailable is %u\n",<BR> stat);<P> return 0;<BR>}<BR> <BR> <P>函数名: arc<BR>功 能: 画一弧线<BR>用 法: void far arc(int x, int y, int stangle, int endangle,int radius);<BR>程序例:<BR>#include <graphics.h><BR>#include <stdlib.h><BR>#include <stdio.h><BR>#include <conio.h><P>int main(void)<BR>{<BR> /* request auto detection */<BR> int gdriver = DETECT, gmode, errorcode;<BR> int midx, midy;<BR> int stangle = 45, endangle = 135;<BR> int radius = 100;<P> /* initialize graphics and local variables */<BR> initgraph(&gdriver, &gmode, "");<P> /* read result of initialization */<BR> errorcode = graphresult(); /* an erroroccurred */<BR> if (errorcode != grOk)<BR> {<BR> printf("Graphics error: %s\n", grapherrormsg(errorcode));<BR> printf("Press any key to halt:");<BR> getch();<P> exit(1); /* terminatewith an error code */<BR> }<P> midx = getmaxx() / 2;<BR> midy = getmaxy() / 2;<BR> setcolor(getmaxcolor());<P> /* draw arc */<BR> arc(midx, midy, stangle, endangle, radius);<P> /* clean up */<BR> getch();<BR> closegraph();<BR> return 0;<BR>}<BR> <BR> <P>函数名: asctime<BR>功 能: 转换日期和时间为ASCII码<BR>用 法: char *asctime(const struct tm *tblock);<BR>程序例:<BR>#include <stdio.h><BR>#include <string.h><BR>#include <time.h><P>int main(void)<BR>{<BR> struct tm t;<BR> char str[80];<P> /* sample loading of tm structure */<P> t.tm_sec = 1; /* Seconds */<BR> t.tm_min = 30; /* Minutes */<BR> t.tm_hour = 9; /* Hour */<BR> t.tm_mday = 22; /* Day of the Month */<BR> t.tm_mon = 11; /* Month */<BR> t.tm_year = 56; /* Year - does not includecentury */<BR> t.tm_wday = 4; /* Day of the week */<BR> t.tm_yday = 0; /* Does not show in asctime */<BR> t.tm_isdst = 0; /* Is Daylight SavTime; doesnot show in asctime */<P> /* converts structure to null terminated<BR> string */<P> strcpy(str, asctime(&t));<BR> printf("%s\n", str);<P> return 0;<BR>}<BR> <BR> <BR> <P>函数名: asin<BR>功 能: 反正弦函数<BR>用 法: double asin(double x);<BR>程序例:<BR>#include <stdio.h><BR>#include <math.h><P>int main(void)<BR>{<BR> double result;<BR> double x = 0.5;<P> result = asin(x);<BR> printf("The arc sin of %lf is %lf\n", x, result);<BR> return(0);<BR>}<BR> <BR> <BR> <P>函数名: assert<BR>功 能: 测试一个条件并可能使程序终止<BR>用 法: void assert(int test);<BR>程序例:<BR>#include <assert.h><BR>#include <stdio.h><BR>#include <stdlib.h><P>struct ITEM {<BR> int key;<BR> int value;<BR>};<P>/* add item to list, make sure list is not null */<BR>void additem(struct ITEM *itemptr) {<BR> assert(itemptr != NULL);<BR> /* add item to list */<BR>}<P>int main(void)<BR>{<BR> additem(NULL);<BR> return 0;<BR>}<BR> <BR> <BR> <P>函数名: atan<BR>功 能: 反正切函数<BR>用 法: double atan(double x);<BR>程序例:<BR>#include <stdio.h><BR>#include <math.h><P>int main(void)<BR>{<BR> double result;<BR> double x = 0.5;<P> result = atan(x);<BR> printf("The arc tangent of %lf is %lf\n", x, result);<BR> return(0);<BR>}<BR> <BR> <P>函数名: atan2<BR>功 能: 计算Y/X的反正切值<BR>用 法: double atan2(double y, double x);<BR>程序例:<BR>#include <stdio.h><BR>#include <math.h><P>int main(void)<BR>{<BR> double result;<BR> double x = 90.0, y = 45.0;<P> result = atan2(y, x);<BR> printf("The arc tangent ratio of %lf is %lf\n", (y / x),result);<BR> return 0;<BR>}<BR> <BR> <P>函数名: atexit<BR>功 能: 注册终止函数<BR>用 法: int atexit(atexit_t func);<BR>程序例:<BR>#include <stdio.h><BR>#include <stdlib.h><P>void exit_fn1(void)<BR>{<BR> printf("Exit function #1 called\n");<BR>}<P>void exit_fn2(void)<BR>{<BR> printf("Exit function #2 called\n");<BR>}<P>int main(void)<BR>{<BR> /* post exit function #1 */<BR> atexit(exit_fn1);<BR> /* post exit function #2 */<BR> atexit(exit_fn2);<BR> return 0;<BR>}<BR> <BR> <BR> <P>函数名: atof<BR>功 能: 把字符串转换成浮点数<BR>用 法: double atof(const char *nptr);<BR>程序例:<BR>#include <stdlib.h><BR>#include <stdio.h><P>int main(void)<BR>{<BR> float f;<BR> char *str = "12345.67";<P> f = atof(str);<BR> printf("string = %s float = %f\n", str, f);<BR> return 0;<BR>}<BR> <BR> <P>函数名: atoi<BR>功 能: 把字符串转换成长整型数<BR>用 法: int atoi(const char *nptr);<BR>程序例:<BR>#include <stdlib.h><BR>#include <stdio.h><P>int main(void)<BR>{<BR> int n;<BR> char *str = "12345.67";<P> n = atoi(str);<BR> printf("string = %s integer = %d\n", str, n);<BR> return 0;<BR>}<BR> <BR> <P>函数名: atol<BR>功 能: 把字符串转换成长整型数<BR>用 法: long atol(const char *nptr);<BR>程序例:<P>#include <stdlib.h><BR>#include <stdio.h><P>int main(void)<BR>{<BR> long l;<BR> char *str = "98765432";<P> l = atol(lstr);<BR> printf("string = %s integer = %ld\n", str, l);<BR> return(0);<BR>}<BR> <P> <A HREF="index.html">返回目录</A><P></BODY></HTML>⌨️ 快捷键说明
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