函数名:?harderr?

功??能:?建立一个硬件错误处理程序?

用??法:?void?harderr(int?(*fptr)());?

程序例:?

/*This?program?will?trap?disk?errors?and?prompt?
the?user?for?action.?Try?running?it?with?no?
disk?in?drive?A:?to?invoke?its?functions.*/?
#include?<stdio.h>?
#include?<conio.h>?
#include?<dos.h>?
#define?IGNORE??0?
#define?RETRY???1?
#define?ABORT???2?
int?buf[500];?
/*define?the?error?messages?for?trapping?disk?problems*/?
static?char?*err_msg[]?=?{?
????"write?protect",?
????"unknown?unit",?
????"drive?not?ready",?
????"unknown?command",?
????"data?error?(CRC)",?
????"bad?request",?
????"seek?error",?
????"unknown?media?type",?
????"sector?not?found",?
????"printer?out?of?paper",?
????"write?fault",?
????"read?fault",?
????"general?failure",?
????"reserved",?
????"reserved",?
????"invalid?disk?change"?
};?
error_win(char?*msg)?
{?
???int?retval;?
???cputs(msg);?
/*prompt?for?user?to?press?a?key?to?abort,?retry,?ignore*/?
???while(1)?
???{?
???????retval=?getch();?
???????if?(retval?==?‘a‘?||?retval?==?‘A‘)?
???????{?
????retval?=?ABORT;?
????break;?
???????}?
???????if?(retval?==?‘r‘?||?retval?==?‘R‘)?
???????{?
????retval?=?RETRY;?
????break;?
???????}?
???????if?(retval?==?‘i‘?||?retval?==?‘I‘)?
???????{?
???????????retval?=?IGNORE;?
???????????break;?
???????}?
???}?
???return(retval);?
}?
/*pragma?warn?-par?reduces?warnings?which?occur?
due?to?the?non?use?of?the?parameters?errval,?
bp?and?si?to?the?handler.*/?
#pragma?warn?-par?
int?handler(int?errval,int?ax,int?bp,int?si)?
{?
???static?char?msg[80];?
???unsigned?di;?
???int?drive;?
???int?errorno;?
???di=?_DI;?
/*if?this?is?not?a?disk?error?then?it?was?
another?device?having?trouble*/?
???if?(ax?<?0)?
???{?
??????/*?report?the?error?*/?
??????error_win("Device?error");?
??????/*?and?return?to?the?program?directly?requesting?abort?*/?
??????hardretn(ABORT);?
???}?
/*?otherwise?it?was?a?disk?error?*/?
???drive?=?ax?&?0x00FF;?
???errorno?=?di?&?0x00FF;?
/*?report?which?error?it?was?*/?
???sprintf(msg,?"Error:?%s?on?drive?%c\r\nA)bort,?R)etry,?I)gnore:?",?
????err_msg[errorno],?‘A‘?+?drive);?
/*?
return?to?the?program?via?dos?interrupt?0x23?with?abort,?retry,?
or?ignore?as?input?by?the?user.?
*/?
???hardresume(error_win(msg));?
???return?ABORT;?
}?
#pragma?warn?+par?
int?main(void)?
{?
/*?
install?our?handler?on?the?hardware?problem?interrupt?
*/?
???harderr(handler);?
???clrscr();?
???printf("Make?sure?there?is?no?disk?in?drive?A:\n");?
???printf("Press?any?key?....\n");?
???getch();?
???printf("Trying?to?access?drive?A:\n");?
???printf("fopen?returned?%p\n",fopen("A:temp.dat",?"w"));?
???return?0;?
}?
??
??

函数名:?hardresume?

功??能:?硬件错误处理函数?

用??法:?void?hardresume(int?rescode);?

程序例:?

??
/*?This?program?will?trap?disk?errors?and?prompt?the?user?for?action.?*/?
/*?Try?running?it?with?no?disk?in?drive?A:?to?invoke?its?functions????*/?
#include?<stdio.h>?
#include?<conio.h>?
#include?<dos.h>?
#define?IGNORE??0?
#define?RETRY???1?
#define?ABORT???2?
int?buf[500];?
/*?define?the?error?messages?for?trapping?disk?problems?*/?
static?char?*err_msg[]?=?{?
????"write?protect",?
????"unknown?unit",?
????"drive?not?ready",?
????"unknown?command",?
????"data?error?(CRC)",?
????"bad?request",?
????"seek?error",?
????"unknown?media?type",?
????"sector?not?found",?
????"printer?out?of?paper",?
????"write?fault",?
????"read?fault",?
????"general?failure",?
????"reserved",?
????"reserved",?
????"invalid?disk?change"?
};?
error_win(char?*msg)?
{?
???int?retval;?
???cputs(msg);?
/*?prompt?for?user?to?press?a?key?to?abort,?retry,?ignore?*/?
???while(1)?
???{?
???????retval=?getch();?
???????if?(retval?==?‘a‘?||?retval?==?‘A‘)?
???????{?
???????????retval?=?ABORT;?
???????????break;?
???????}?
???????if?(retval?==?‘r‘?||?retval?==?‘R‘)?
???????{?
???????????retval?=?RETRY;?
???????????break;?
???????}?
???????if?(retval?==?‘i‘?||?retval?==?‘I‘)?
???????{?
???????????retval?=?IGNORE;?
???????????break;?
???????}?
???}?
???return(retval);?
}?
/*?pragma?warn?-par?reduces?warnings?which?occur?due?to?the?non?use?*/?
/*?of?the?parameters?errval,?bp?and?si?to?the?handler.??????????????*/?
#pragma?warn?-par?
int?handler(int?errval,int?ax,int?bp,int?si)?
{?
???static?char?msg[80];?
???unsigned?di;?
???int?drive;?
???int?errorno;?
???di=?_DI;?
/*?if?this?is?not?a?disk?error?then?it?was?another?device?having?trouble?*/?
???if?(ax?<?0)?
???{?
??????/*?report?the?error?*/?
??????error_win("Device?error");?
??????/*?and?return?to?the?program?directly?
??????requesting?abort?*/?
??????hardretn(ABORT);?
???}?
/*?otherwise?it?was?a?disk?error?*/?
???drive?=?ax?&?0x00FF;?
???errorno?=?di?&?0x00FF;?
/*?report?which?error?it?was?*/?
???sprintf(msg,?"Error:?%s?on?drive?%c\r\nA)bort,?R)etry,?I)gnore:?",?
???????????err_msg[errorno],?‘A‘?+?drive);?
/*?return?to?the?program?via?dos?interrupt?0x23?with?abort,?retry?*/?
/*?or?ignore?as?input?by?the?user.??*/?
???hardresume(error_win(msg));?
???return?ABORT;?
}?
#pragma?warn?+par?
int?main(void)?
{?
/*?install?our?handler?on?the?hardware?problem?interrupt?*/?
???harderr(handler);?
???clrscr();?
???printf("Make?sure?there?is?no?disk?in?drive?A:\n");?
???printf("Press?any?key?....\n");?
???getch();?
???printf("Trying?to?access?drive?A:\n");?
???printf("fopen?returned?%p\n",fopen("A:temp.dat",?"w"));?
???return?0;?
}?
??
??

函数名:?highvideo?

功??能:?选择高亮度文本字符?

用??法:?void?highvideo(void);?

程序例:?

#include?<conio.h>?
int?main(void)?
{?
???clrscr();?
???lowvideo();?
???cprintf("Low?Intensity?text\r\n");?
???highvideo();?
???gotoxy(1,2);?
???cprintf("High?Intensity?Text\r\n");?
???return?0;?
}?
??
??

函数名:?hypot?

功??能:?计算直角三角形的斜边长?

用??法:?double?hypot(double?x,?double?y);?

程序例:?

#include?<stdio.h>?
#include?<math.h>?
int?main(void)?
{?
???double?result;?
???double?x?=?3.0;?
???double?y?=?4.0;?
???result?=?hypot(x,?y);?
???printf("The?hypotenuse?is:?%lf\n",?result);?
???return?0;?
}?
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