c函数大全.txt

关于c中的一些函数用法的说明

return 0; 
} 




函数名: clrscr 
功 能: 清除文本模式窗口 
用 法: void clrscr(void); 
程序例: 

#include 

int main(void) 
{ 
int i; 

clrscr(); 
for (i = 0; i < 20; i++) 
cprintf("%d\r\n", i); 
cprintf("\r\nPress any key to clear screen"); 
getch(); 

clrscr(); 
cprintf("The screen has been cleared!"); 
getch(); 

return 0; 
} 




函数名: coreleft 
功 能: 返回未使用内存的大小 
用 法: unsigned coreleft(void); 
程序例: 

#include 
#include 

int main(void) 
{ 
printf("The difference between the highest allocated block and\n"); 
printf("the top of the heap is: %lu bytes\n", (unsigned long) coreleft()); 

return 0; 
} 


函数名: cos 
功 能: 余弦函数 
用 法: double cos(double x); 
程序例: 

#include 
#include 

int main(void) 
{ 
double result; 
double x = 0.5; 

result = cos(x); 
printf("The cosine of %lf is %lf\n", x, result); 
return 0; 
} 




函数名: cosh 
功 能: 双曲余弦函数 
用 法: dluble cosh(double x); 
程序例: 

#include 
#include 

int main(void) 
{ 
double result; 
double x = 0.5; 

result = cosh(x); 
printf("The hyperboic cosine of %lf is %lf\n", x, result); 
return 0; 
} 




函数名: country 
功 能: 返回与国家有关的信息 
用 法: struct COUNTRY *country(int countrycode, struct country *country); 
程序例: 

#include 
#include 

#define USA 0 

int main(void) 
{ 
struct COUNTRY country_info; 

country(USA, &country_info); 
printf("The currency symbol for the USA is: %s\n", 
country_info.co_curr); 
return 0; 
} 




函数名: cprintf 
功 能: 送格式化输出至屏幕 
用 法: int cprintf(const char *format[, argument, ...]); 
程序例: 

#include 

int main(void) 
{ 
/* clear the screen */ 
clrscr(); 

/* create a text window */ 
window(10, 10, 80, 25); 

/* output some text in the window */ 
cprintf("Hello world\r\n"); 

/* wait for a key */ 
getch(); 
return 0; 
} 




函数名: cputs 
功 能: 写字符到屏幕 
用 法: void cputs(const char *string); 
程序例: 

#include 

int main(void) 
{ 
/* clear the screen */ 
clrscr(); 

/* create a text window */ 
window(10, 10, 80, 25); 

/* output some text in the window */ 
cputs("This is within the window\r\n"); 

/* wait for a key */ 
getch(); 
return 0; 
} 




函数名: _creat creat 
功 能: 创建一个新文件或重写一个已存在的文件 
用 法: int creat (const char *filename, int permiss); 
程序例: 

#include 
#include 
#include 
#include 

int main(void) 
{ 
int handle; 
char buf[11] = "0123456789"; 

/* change the default file mode from text to binary */ 
_fmode = O_BINARY; 

/* create a binary file for reading and writing */ 
handle = creat("DUMMY.FIL", S_IREAD | S_IWRITE); 

/* write 10 bytes to the file */ 
write(handle, buf, strlen(buf)); 

/* close the file */ 
close(handle); 
return 0; 
} 


函数名: creatnew 
功 能: 创建一个新文件 
用 法: int creatnew(const char *filename, int attrib); 
程序例: 

#include 
#include 
#include 
#include 
#include 

int main(void) 
{ 
int handle; 
char buf[11] = "0123456789"; 

/* attempt to create a file that doesn't already exist */ 
handle = creatnew("DUMMY.FIL", 0); 

if (handle == -1) 
printf("DUMMY.FIL already exists.\n"); 
else 
{ 
printf("DUMMY.FIL successfully created.\n"); 
write(handle, buf, strlen(buf)); 
close(handle); 
} 
return 0; 
} 




函数名: creattemp 
功 能: 创建一个新文件或重写一个已存在的文件 
用 法: int creattemp(const char *filename, int attrib); 
程序例: 

#include 
#include 
#include 

int main(void) 
{ 
int handle; 
char pathname[128]; 

strcpy(pathname, "\\"); 

/* create a unique file in the root directory */ 
handle = creattemp(pathname, 0); 

printf("%s was the unique file created.\n", pathname); 
close(handle); 
return 0; 
} 




函数名: cscanf 
功 能: 从控制台执行格式化输入 
用 法: int cscanf(char *format[,argument, ...]); 
程序例: 

#include 

int main(void) 
{ 
char string[80]; 

/* clear the screen */ 
clrscr(); 

/* Prompt the user for input */ 
cprintf("Enter a string with no spaces:"); 

/* read the input */ 
cscanf("%s", string); 

/* display what was read */ 
cprintf("\r\nThe string entered is: %s", string); 
return 0; 
} 




函数名: ctime 
功 能: 把日期和时间转换为字符串 
用 法: char *ctime(const time_t *time); 
程序例: 

#include 
#include 

int main(void) 
{ 
time_t t; 

time(&t); 
printf("Today's date and time: %s\n", ctime(&t)); 
return 0; 
} 




函数名: ctrlbrk 
功 能: 设置Ctrl-Break处理程序 
用 法: void ctrlbrk(*fptr)(void); 
程序例: 

#include 
#include 

#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; 
} 

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 

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 

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 
#include 
#include 
#include 

/* 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 
#include 
#include 
#include 

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 
#include 
#include 

#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 

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 
#include 

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 
#include 
#include 
#include 

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 
#include 
#include 
#include 

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 
#include 
#include 
#include 

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;