函数名: tan功 能: 正切函数用 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 %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 <stdio.h>#include <math.h>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 <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 %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 <conio.h>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 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("\r\n"); textcolor(i+1); textbackground(i); } 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 <conio.h>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 <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: %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 <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 <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: %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 <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 <stdio.h>#include <process.h>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 <stdio.h>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 <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("%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 <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("%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 <time.h>#include <stdlib.h>#include <stdio.h>int main(void){ time_t td; putenv("TZ=PST8PDT"); tzset(); time(&td); printf("Current time = %s\n", asctime(localtime(&td))); return 0;}
