c语言 字母是什么类,C语言库函数(T类字母)

函数名: tan

功  能: 正切函数

用  法: double tan(double x);

程序例:

#include

#include

int main(void)

{

double result, x;

x = 0.5;

result = tan(x);

printf("The tan of %lf is %lf\n", x, result);

return 0;

}

函数名: tanh

功  能: 双曲正切函数

用  法: double tanh(double x);

程序例:

#include

#include

int main(void)

{

double result, x;

x = 0.5;

result = tanh(x);

printf("The hyperbolic tangent of %lf is %lf\n", x, result);

return 0;

}

函数名: tell

功  能: 取文件指针的当前位置

用  法: long tell(int handle);

程序例:

#include

#include

#include

#include

int main(void)

{

int handle;

char msg[] = "Hello world";

if ((handle = open("TEST.$$$", O_CREAT | O_TEXT | O_APPEND)) == -1)

{

perror("Error:");

return 1;

}

write(handle, msg, strlen(msg));

printf("The file pointer is at byte %ld\n", tell(handle));

close(handle);

return 0;

}

函数名: textattr

功  能: 设置文本属性

用  法: void textattr(int attribute);

程序例:

#include

int main(void)

{

int i;

clrscr();

for (i=0; i<9; i++)

{

textattr(i + ((i+1) << 4));

cprintf("This is a test\r\n");

}

return 0;

}

函数名: textbackground

功  能: 选择新的文本背景颜色

用  法: void textint color);

程序例:

#include

int main(void)

{

int i, j;

clrscr();

for (i=0; i<9; i++)

{

for (j=0; j<80; j++)

cprintf("C");

cprintf("\r\n");

textcolor(i+1);

texti);

}

return 0;

}

函数名: textcolor

功  能: 在文本模式中选择新的字符颜色

用  法: void textcolor(int color);

程序例:

#include

int main(void)

{

int i;

for (i=0; i<15; i++)

{

textcolor(i);

cprintf("Foreground Color\r\n");

}

return 0;

}

函数名: textheight

功  能: 返回以像素为单位的字符串高度

用  法: int far textheight(char far *textstring);

程序例:

#include

#include

#include

#include

int main(void)

{

/* request auto detection */

int gdriver = DETECT, gmode, errorcode;

int y = 0;

int i;

char msg[80];

/* 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();

exit(1); /* terminate with an error code */

}

/* draw some text on the screen */

for (i=1; i<11; i++)

{

/* select the text style, direction, and size */

settextstyle(TRIPLEX_FONT, HORIZ_DIR, i);

/* create a message string */

sprintf(msg, "Size: %d", i);

/* output the message */

outtextxy(1, y, msg);

/* advance to the next text line */

y += textheight(msg);

}

/* clean up */

getch();

closegraph();

return 0;

}

函数名: textmode

功  能: 将屏幕设置成文本模式

用  法: void textmode(int mode);

程序例:

#include

int main(void)

{

textmode(BW40);

cprintf("ABC");

getch();

textmode(C40);

cprintf("ABC");

getch();

textmode(BW80);

cprintf("ABC");

getch();

textmode(C80);

cprintf("ABC");

getch();

textmode(MONO);

cprintf("ABC");

getch();

return 0;

}

函数名: textwidth

功  能: 返回以像素为单位的字符串宽度

用  法: int far textwidth(char far *textstring);

程序例:

#include

#include

#include

#include

int main(void)

{

/* request auto detection */

int gdriver = DETECT, gmode, errorcode;

int x = 0, y = 0;

int i;

char msg[80];

/* 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();

exit(1); /* terminate with an error code */

}

y = getmaxy() / 2;

settextjustify(LEFT_TEXT, CENTER_TEXT);

for (i=1; i<11; i++)

{

/* select the text style, direction, and size */

settextstyle(TRIPLEX_FONT, HORIZ_DIR, i);

/* create a message string */

sprintf(msg, "Size: %d", i);

/* output the message */

outtextxy(x, y, msg);

/* advance to the end of the text */

x += textwidth(msg);

}

/* clean up */

getch();

closegraph();

return 0;

}

函数名: time

功  能: 取一天的时间

用  法: logn time(long *tloc);

程序例:

#include

#include

#include

int main(void)

{

time_t t;

t = time(NULL);

printf("The number of seconds since January 1, 1970 is %ld",t);

return 0;

}

函数名: tmpfile

功  能: 以二进制方式打开暂存文件

用  法: FILE *tmpfile(void);

程序例:

#include

#include

int main(void)

{

FILE *tempfp;

tempfp = tmpfile();

if (tempfp)

printf("Temporary file created\n");

else

{

printf("Unable to create temporary file\n");

exit(1);

}

return 0;

}

函数名: tmpnam

功  能: 创建一个唯一的文件名

用  法: char *tmpnam(char *sptr);

程序例:

#include

int main(void)

{

char name[13];

tmpnam(name);

printf("Temporary name: %s\n", name);

return 0;

}

函数名: tolower

功  能: 把字符转换成小写字母

用  法: int tolower(int c);

程序例:

#include

#include

#include

int main(void)

{

int length, i;

char *string = "THIS IS A STRING";

length = strlen(string);

for (i=0; i

{

string[i] = tolower(string[i]);

}

printf("%s\n",string);

return 0;

}

函数名: toupper

功  能: 把字符转换成大写字母

用  法: int toupper(int c);

程序例:

#include

#include

#include

int main(void)

{

int length, i;

char *string = "this is a string";

length = strlen(string);

for (i=0; i

{

string[i] = toupper(string[i]);

}

printf("%s\n",string);

return 0;

}

函数名: tzset

功  能: UNIX时间兼容函数

用  法: void tzset(void);

程序例:

#include

#include

#include

int main(void)

{

time_t td;

putenv("TZ=PST8PDT");

tzset();

time(&td);

printf("Current time = %s\n", asctime(localtime(&td)));

return 0;

}