C语言库函数(C类字母之三)

#include

int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int x, y;

/* initialize graphics mode */
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 */
}

x = getmaxx() / 2;
y = getmaxy() / 2;

/* output a message */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, "Press a key to close the graphics system:");

/* wait for a key */
getch();

/* closes down the graphics system */
closegraph();

printf("We're now back in text mode.\n");
printf("Press any key to halt:");
getch();
return 0;
}




函数名: clreol
功 能: 在文本窗口中清除字符到行末
用 法: void clreol(void);
程序例:

#include

int main(void)

{
clrscr();
cprintf("The function CLREOL clears all characters from the\r\n");
cprintf("cursor position to the end of the line within the\r\n");
cprintf("current text window, without moving the cursor.\r\n");
cprintf("Press any key to continue . . .");
gotoxy(14, 4);
getch();

clreol();
getch();

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 */