c语言函数大全.txt

c语言函数大全

#include <stdio.h> 
#include <dos.h> 



#define ABORT 0 



int c_break(void) 

{ 
printf("Control-Break pressed. Program aborting ...\n"); 
return (ABORT); 
} 



int main(void) 
{ 
ctrlbrk(c_break); 
for(;;) 
{ 
printf("Looping... Press to quit:\n"); 
} 
return 0; 
} 

　 C语言函数库 

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[gdriver]); 
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 #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;} 





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 */ 

}