站長(zhǎng)資訊網(wǎng)函數(shù)名: tan
功 能: 正切函數(shù)
用 法: double tan(double x);
程序例:
#include <stdio.h>
#include <math.h>
int main(void)
{
double result, x;
x = 0.5;
result = tan(x);
printf(“The tan of %lf is %lfn”, x, result);
return 0;
}
函數(shù)名: tanh
功 能: 雙曲正切函數(shù)
用 法: double tanh(double x);
程序例:
#include <stdio.h>
#include <math.h>
int main(void)
{
double result, x;
x = 0.5;
result = tanh(x);
printf(“The hyperbolic tangent of %lf is %lfn”, x, result);
return 0;
}
函數(shù)名: tell
功 能: 取文件指針的當(dāng)前位置
用 法: long tell(int handle);
程序例:
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>
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 %ldn”, tell(handle));
close(handle);
return 0;
}
函數(shù)名: textattr
功 能: 設(shè)置文本屬性
用 法: void textattr(int attribute);
程序例:
#include <conio.h>
int main(void)
{
int i;
clrscr();
for (i=0; i<9; i++)
{
textattr(i + ((i+1) << 4));
cprintf(“This is a testrn”);
}
return 0;
}
函數(shù)名: textbackground
功 能: 選擇新的文本背景顏色
用 法: void textbackground(int color);
程序例:
#include <conio.h>
int main(void)
{
int i, j;
clrscr();
for (i=0; i<9; i++)
{
for (j=0; j<80; j++)
cprintf(“C”);
cprintf(“rn”);
textcolor(i+1);
textbackground(i);
}
return 0;
}
函數(shù)名: textcolor
功 能: 在文本模式中選擇新的字符顏色
用 法: void textcolor(int color);
程序例:
#include <conio.h>
int main(void)
{
int i;
for (i=0; i<15; i++)
{
textcolor(i);
cprintf(“Foreground Colorrn”);
}
return 0;
}
函數(shù)名: textheight
功 能: 返回以像素為單位的字符串高度
用 法: int far textheight(char far *textstring);
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 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: %sn”, 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;
}
函數(shù)名: textmode
功 能: 將屏幕設(shè)置成文本模式
用 法: void textmode(int mode);
程序例:
#include <conio.h>
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;
}
函數(shù)名: textwidth
功 能: 返回以像素為單位的字符串寬度
用 法: int far textwidth(char far *textstring);
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 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: %sn”, 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;
}
函數(shù)名: time
功 能: 取一天的時(shí)間
用 法: logn time(long *tloc);
程序例:
#include <time.h>
#include <stdio.h>
#include <dos.h>
int main(void)
{
time_t t;
t = time(NULL);
printf(“The number of seconds since January 1, 1970 is %ld”,t);
return 0;
}
函數(shù)名: tmpfile
功 能: 以二進(jìn)制方式打開(kāi)暫存文件
用 法: FILE *tmpfile(void);
程序例:
#include <stdio.h>
#include <process.h>
int main(void)
{
FILE *tempfp;
tempfp = tmpfile();
if (tempfp)
printf(“Temporary file createdn”);
else
{
printf(“Unable to create temporary filen”);
exit(1);
}
return 0;
}
函數(shù)名: tmpnam
功 能: 創(chuàng)建一個(gè)唯一的文件名
用 法: char *tmpnam(char *sptr);
程序例:
#include <stdio.h>
int main(void)
{
char name[13];
tmpnam(name);
printf(“Temporary name: %sn”, name);
return 0;
}
函數(shù)名: tolower
功 能: 把字符轉(zhuǎn)換成小寫(xiě)字母
用 法: int tolower(int c);
程序例:
#include <string.h>
#include <stdio.h>
#include <ctype.h>
int main(void)
{
int length, i;
char *string = “THIS IS A STRING”;
length = strlen(string);
for (i=0; i<length; i++)
{
string[i] = tolower(string[i]);
}
printf(“%sn”,string);
return 0;
}
函數(shù)名: toupper
功 能: 把字符轉(zhuǎn)換成大寫(xiě)字母
用 法: int toupper(int c);
程序例:
#include <string.h>
#include <stdio.h>
#include <ctype.h>
int main(void)
{
int length, i;
char *string = “this is a string”;
length = strlen(string);
for (i=0; i<length; i++)
{
string[i] = toupper(string[i]);
}
printf(“%sn”,string);
return 0;
}
函數(shù)名: tzset
功 能: UNIX時(shí)間兼容函數(shù)
用 法: void tzset(void);
程序例:
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
time_t td;
putenv(“TZ=PST8PDT”);
tzset();
time(&td);
printf(“Current time = %sn”, asctime(localtime(&td)));
return 0;
}
