C语言库函数(S类字母)

2019-11-17 05:42:54

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函数名: sbrk
功  能: 改变数据段空间位置
用  法: char *sbrk(int incr);
程序例:

#include <stdio.h>
#include <alloc.h>

int main(void)
{
   PRintf("Changing allocation with sbrk()/n");
   printf("Before sbrk() call: %lu bytes free/n",
   (unsigned long) coreleft());
   sbrk(1000);
   printf(" After sbrk() call: %lu bytes free/n",
   (unsigned long) coreleft());
   return 0;
}



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

#include <stdio.h>
#include <conio.h>

int main(void)
{
   char label[20];
   char name[20];
   int entries = 0;
   int loop, age;
   double salary;

   strUCt Entry_struct
   {
      char  name[20];
      int   age;
      float salary;
   } entry[20];

/* Input a label as a string of characters restricting to 20 characters */
   printf("/n/nPlease enter a label for the chart: ");
   scanf("%20s", label);
   fflush(stdin);  /* flush the input stream in case of bad input */

/* Input number of entries as an integer */
   printf("How many entries will there be? (less than 20) ");
   scanf("%d", &entries);
   fflush(stdin);   /* flush the input stream in case of bad input */

/* input a name restricting input to only letters upper or lower case */
   for (loop=0;loop<entries;++loop)
   {
      printf("Entry %d/n", loop);
      printf("  Name   : ");
      scanf("%[A-Za-z]", entry[loop].name);
      fflush(stdin);  /* flush the input stream in case of bad input */

/* input an age as an integer */
      printf("  Age    : ");
      scanf("%d", &entry[loop].age);
      fflush(stdin);  /* flush the input stream in case of bad input */

/* input a salary as a float */
      printf("  Salary : ");
      scanf("%f", &entry[loop].salary);
      fflush(stdin); /* flush the input stream in case of bad input */
   }

/* Input a name, age and salary as a string, integer, and double */
   printf("/nPlease enter your name, age and salary/n");
   scanf("%20s %d %lf", name, &age, &salary);


/* Print out the data that was input */
   printf("/n/nTable %s/n",label);
   printf("Compiled by %s  age %d  $%15.2lf/n", name, age, salary);
   printf("-----------------------------------------------------/n");
   for (loop=0;loop<entries;++loop)
      printf("%4d  %-20s  %5d  %15.2lf/n",
         loop + 1,
  entry[loop].name,
  entry[loop].age,
         entry[loop].salary);
   printf("-----------------------------------------------------/n");
   return 0;

}



函数名: searchpath
功  能: 搜索DOS路径
用  法: char *searchpath(char *filename);
程序例:

#include <stdio.h>
#include <dir.h>

int main(void)
{
   char *p;

   /* Looks for TLINK and returns a pointer
      to the path  */
   p = searchpath("TLINK.EXE");
   printf("Search for TLINK.EXE : %s/n", p);

   /* Looks for non-existent file  */
   p = searchpath("NOTEXIST.FIL");
   printf("Search for NOTEXIST.FIL : %s/n", p);

   return 0;
}



函数名: sector
功  能: 画并填充椭圆扇区
用  法: void far sector(int x, int y, int stangle, int endangle);
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 midx, midy, i;
   int stangle = 45, endangle = 135;
   int xrad = 100, yrad = 50;

   /* 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 */

   }

   midx = getmaxx() / 2;
   midy = getmaxy() / 2;

   /* loop through the fill patterns */
   for (i=EMPTY_FILL; i<USER_FILL; i++)
   {
      /* set the fill style */
      setfillstyle(i, getmaxcolor());

      /* draw the sector slice */
      sector(midx, midy, stangle, endangle, xrad, yrad);

      getch();
   }

   /* clean up */
   closegraph();
   return 0;
}


函数名: segread
功  能: 读段寄存器值
用  法: void segread(struct SREGS *segtbl);
程序例:

#include <stdio.h>
#include <dos.h>

int main(void)
{
   struct SREGS segs;

   segread(&segs);
   printf("Current segment register settings/n/n");
   printf("CS: %X   DS: %X/n", segs.cs, segs.ds);
   printf("ES: %X   SS: %X/n", segs.es, segs.ss);

   return 0;
}



函数名: setactivepage
功  能: 设置图形输出活动页
用  法: void far setactivepage(int pagenum);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int main(void)
{
   /* select a driver and mode that supports */
   /* multiple pages.                        */
   int gdriver = EGA, gmode = EGAHI, errorcode;
   int x, y, ht;

   /* 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 */
   }

   x = getmaxx() / 2;
   y = getmaxy() / 2;
   ht = textheight("W");

   /*  select the off screen page for drawing */
   setactivepage(1);

   /* draw a line on page #1 */
   line(0, 0, getmaxx(), getmaxy());

   /* output a message on page #1 */
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   outtextxy(x, y, "This is page #1:");
   outtextxy(x, y+ht, "Press any key to halt:");

   /* select drawing to page #0 */
   setactivepage(0);

   /* output a message  on page #0 */
   outtextxy(x, y, "This is page #0.");
   outtextxy(x, y+ht, "Press any key to view page #1:");
   getch();

   /* select page #1 as the visible page */
   setvisualpage(1);

   /* clean up */
   getch();
   closegraph();
   return 0;
}



函数名: setallpallette
功  能: 按指定方式改变所有的调色板颜色
用  法: void far setallpallette(struct palette, far *pallette);
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;
   struct palettetype pal;
   int color, maxcolor, ht;
   int y = 10;
   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 */
   }

   maxcolor = getmaxcolor();
   ht = 2 * textheight("W");

   /* grab a copy of the palette */
   getpalette(&pal);

   /* display the default palette colors */
   for (color=1; color<=maxcolor; color++)
   {
      setcolor(color);
      sprintf(msg, "Color: %d", color);
      outtextxy(1, y, msg);
      y += ht;
   }

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

   /* black out the colors one by one */
   for (color=1; color<=maxcolor; color++)
   {
      setpalette(color, BLACK);
      getch();
   }

   /* restore the palette colors */

   setallpalette(&pal);

   /* clean up */
   getch();
   closegraph();
   return 0;
}



函数名: setaspectratio
功  能: 设置图形纵横比
用  法: void far setaspectratio(int xasp, int yasp);
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 xasp, yasp, midx, midy;

   /* 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 */
   }

   midx = getmaxx() / 2;
   midy = getmaxy() / 2;
   setcolor(getmaxcolor());

   /* get current aspect ratio settings */
   getaspectratio(&xasp, &yasp);

   /* draw normal circle */
   circle(midx, midy, 100);
   getch();

   /* claer the screen */
   cleardevice();

   /* adjust the aspect for a wide circle */
   setaspectratio(xasp/2, yasp);
   circle(midx, midy, 100);

   getch();

   /* adjust the aspect for a narrow circle */
   cleardevice();
   setaspectratio(xasp, yasp/2);
   circle(midx, midy, 100);

   /* clean up */
   getch();
   closegraph();
   return 0;
}



函数名: setbkcolor
功  能: 用调色板设置当前背景颜色
用  法: void far setbkcolor(int color);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int main(void)
{
   /* select a driver and mode that supports */
   /* multiple background colors.            */
   int gdriver = EGA, gmode = EGAHI, errorcode;
   int bkcol, maxcolor, x, y;
   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 */
   }

   /* maximum color index supported */
   maxcolor = getmaxcolor();

   /* for centering text messages */
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   x = getmaxx() / 2;
   y = getmaxy() / 2;

   /* loop through the available colors */

   for (bkcol=0; bkcol<=maxcolor; bkcol++)
   {
      /* clear the screen */
      cleardevice();

      /* select a new background color */
      setbkcolor(bkcol);

      /* output a messsage */
      if (bkcol == WHITE)
  setcolor(EGA_BLUE);
      sprintf(msg, "Background color: %d", bkcol);
      outtextxy(x, y, msg);
      getch();
   }

   /* clean up */
   closegraph();
   return 0;
}



函数名: setblock
功  能: 修改先前已分配的DOS存储段大小
用  法: int setblock(int seg, int newsize);
程序例:

#include <dos.h>
#include <alloc.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
   unsigned int size, segp;
   int stat;

   size = 64; /* (64 x 16) = 1024 bytes */
   stat = allocmem(size, &segp);
   if (stat == -1)
      printf("Allocated memory at segment: %X/n", segp);
   else
   {
      printf("Failed: maximum number of paragraphs available is %d/n",
      stat);
      exit(1);
   }

   stat = setblock(segp, size * 2);
   if (stat == -1)
      printf("EXPanded memory block at segment: %X/n", segp);
   else

      printf("Failed: maximum number of paragraphs available is %d/n",
             stat);

   freemem(segp);

   return 0;
}



函数名: setbuf
功  能: 把缓冲区与流相联
用  法: void setbuf(FILE *steam, char *buf);
程序例:

#include <stdio.h>

/* BUFSIZ is defined in stdio.h */
char outbuf[BUFSIZ];

int main(void)
{
   /* attach a buffer to the standard output stream */
   setbuf(stdout, outbuf);

   /* put some characters into the buffer */
   puts("This is a test of buffered output./n/n");
   puts("This output will go into outbuf/n");
   puts("and won't appear until the buffer/n");
   puts("fills up or we flush the stream./n");

   /* flush the output buffer */
   fflush(stdout);

   return 0;
}



函数名: setcbrk
功  能: 设置Control-break
用  法: int setcbrk(int value);
程序例:

#include <dos.h>
#include <conio.h>
#include <stdio.h>

int main(void)
{
   int break_flag;

   printf("Enter 0 to turn control break off/n");
   printf("Enter 1 to turn control break on/n");

   break_flag = getch() - 0;

   setcbrk(break_flag);

   if (getcbrk())
      printf("Cntrl-brk flag is on/n");
   else
      printf("Cntrl-brk flag is off/n");
   return 0;
}




函数名: setcolor
功  能: 设置当前画线颜色
用  法: void far setcolor(int color);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int main(void)
{
   /* select a driver and mode that supports */
   /* multiple drawing colors.               */
   int gdriver = EGA, gmode = EGAHI, errorcode;
   int color, maxcolor, x, y;
   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 */
   }

   /* maximum color index supported */
   maxcolor = getmaxcolor();

   /* for centering text messages */
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   x = getmaxx() / 2;
   y = getmaxy() / 2;

   /* loop through the available colors */
   for (color=1; color<=maxcolor; color++)
   {
      /* clear the screen */
      cleardevice();

      /* select a new background color */
      setcolor(color);

      /* output a messsage */

      sprintf(msg, "Color: %d", color);
      outtextxy(x, y, msg);
      getch();
   }

   /* clean up */
   closegraph();
   return 0;
}



函数名: setdate
功  能: 设置DOS日期
用  法: void setdate(struct date *dateblk);
程序例:

#include <stdio.h>
#include <process.h>
#include <dos.h>

int main(void)
{
   struct date reset;
   struct date save_date;

   getdate(&save_date);
   printf("Original date:/n");
   system("date");

   reset.da_year = 2001;
   reset.da_day = 1;
   reset.da_mon = 1;
   setdate(&reset);

   printf("Date after setting:/n");
   system("date");

   setdate(&save_date);
   printf("Back to original date:/n");
   system("date");

   return 0;
}



函数名: setdisk
功  能: 设置当前磁盘驱动器
用  法: int setdisk(int drive);
程序例:

#include <stdio.h>
#include <dir.h>

int main(void)
{
   int save, disk, disks;

   /* save original drive */
   save = getdisk();

   /* print number of logic drives */
   disks = setdisk(save);
   printf("%d logical drives on the system/n/n", disks);

   /* print the drive letters available */
   printf("Available drives:/n");
   for (disk = 0;disk < 26;++disk)

   {
      setdisk(disk);
      if (disk == getdisk())
         printf("%c: drive is available/n", disk + 'a');
   }
   setdisk(save);

   return 0;
}



函数名: setdta
功  能: 设置磁盘传输区地址
用  法: void setdta(char far *dta);
程序例:

#include <process.h>
#include <string.h>
#include <stdio.h>
#include <dos.h>

int main(void)
{
   char line[80], far *save_dta;
   char buffer[256] = "SETDTA test!";
   struct fcb blk;
   int result;

   /* get new file name from user */
   printf("Enter a file name to create:");
   gets(line);

   /* parse the new file name to the dta */
   parsfnm(line, &blk, 1);
   printf("%d %s/n", blk.fcb_drive, blk.fcb_name);

   /* request DOS services to create file */
   if (bdosptr(0x16, &blk, 0) == -1)
   {
      perror("Error creating file");
      exit(1);
   }

   /* save old dta and set new dta */
   save_dta = getdta();
   setdta(buffer);

   /* write new records */
   blk.fcb_recsize = 256;
   blk.fcb_random = 0L;
   result = randbwr(&blk, 1);
   printf("result = %d/n", result);

   if (!result)
      printf("Write OK/n");
   else
   {
      perror("Disk error");

      exit(1);
   }

   /* request DOS services to close the file */
   if (bdosptr(0x10, &blk, 0) == -1)
   {
      perror("Error closing file");
      exit(1);
   }

   /* reset the old dta */
   setdta(save_dta);
   return 0;
}



函数名: setfillpattern
功  能: 选择用户定义的填充模式
用  法: void far setfillpattern(char far *upattern, int color);
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 maxx, maxy;

   /* a user defined fill pattern */
   char pattern[8] = {0x00, 0x70, 0x20, 0x27, 0x24, 0x24, 0x07, 0x00};

   /* 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 */
   }

   maxx = getmaxx();
   maxy = getmaxy();
   setcolor(getmaxcolor());

   /* select a user defined fill pattern */
   setfillpattern(pattern, getmaxcolor());

   /* fill the screen with the pattern */
   bar(0, 0, maxx, maxy);

   /* clean up */
   getch();
   closegraph();
   return 0;
}



函数名: setfillstyle
功  能: 设置填充模式和颜色
用  法: void far setfillstyle(int pattern, int color);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <conio.h>

/* the names of the fill styles supported */
char *fname[] = { "EMPTY_FILL",
                  "SOLID_FILL",
                  "LINE_FILL",
                  "LTSLASH_FILL",
                  "SLASH_FILL",
                  "BKSLASH_FILL",
                  "LTBKSLASH_FILL",
    "HATCH_FILL",
                  "XHATCH_FILL",
                  "INTERLEAVE_FILL",
                  "WIDE_DOT_FILL",
                  "CLOSE_DOT_FILL",
    "USER_FILL"
                };

int main(void)
{
   /* request auto detection */
   int gdriver = DETECT, gmode, errorcode;
   int style, midx, midy;
   char stylestr[40];

   /* 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 */
   }

   midx = getmaxx() / 2;
   midy = getmaxy() / 2;

   for (style = EMPTY_FILL; style < USER_FILL; style++)
   {
      /* select the fill style */
      setfillstyle(style, getmaxcolor());

      /* convert style into a string */
      strcpy(stylestr, fname[style]);

      /* fill a bar */
      bar3d(0, 0, midx-10, midy, 0, 0);

      /* output a message */
      outtextxy(midx, midy, stylestr);

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

   /* clean up */
   getch();
   closegraph();
   return 0;
}



函数名: setftime
功  能: 设置文件日期和时间
用  法: int setftime(int handle, struct ftime *ftimep);
程序例:

#include <stdio.h>
#include <process.h>
#include <fcntl.h>
#include <io.h>

int main(void)
{
   struct ftime filet;
   FILE *fp;

   if ((fp = fopen("TEST.$$$", "w")) == NULL)
   {
      perror("Error:");
      exit(1);
   }

   fprintf(fp, "testing.../n");

   /* load ftime structure with new time and date */
   filet.ft_tsec = 1;
   filet.ft_min = 1;
   filet.ft_hour = 1;
   filet.ft_day = 1;
   filet.ft_month = 1;
   filet.ft_year = 21;

   /* show current Directory for time and date */
   system("dir TEST.$$$");

   /* change the time and date stamp*/
   setftime(fileno(fp), &filet);

   /* close and remove the temporary file */
   fclose(fp);

   system("dir TEST.$$$");

   unlink("TEST.$$$");
   return 0;
}



函数名: setgraphbufsize
功  能: 改变内部图形缓冲区的大小
用  法: unsigned far setgraphbufsize(unsigned bufsize);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

#define BUFSIZE 1000 /* internal graphics buffer size */

int main(void)
{
   /* request auto detection */
   int gdriver = DETECT, gmode, errorcode;
   int x, y, oldsize;
   char msg[80];

   /* set the size of the internal graphics buffer */
   /* before making a call to initgraph.           */
   oldsize = setgraphbufsize(BUFSIZE);

   /* 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 */
   }

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

   /* output some messages */
   sprintf(msg, "Graphics buffer size: %d", BUFSIZE);
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   outtextxy(x, y, msg);
   sprintf(msg, "Old graphics buffer size: %d", oldsize);
   outtextxy(x, y+textheight("W"), msg);

   /* clean up */
   getch();
   closegraph();
   return 0;
}




函数名: setgraphmode
功  能: 将系统设置成图形模式且清屏
用  法: void far setgraphmode(int mode);
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, y;

   /* 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 */
   }

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

   /* output a message */
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   outtextxy(x, y, "Press any key to exit graphics:");
   getch();

   /* restore system to text mode */
   restorecrtmode();
   printf("We're now in text mode./n");
   printf("Press any key to return to graphics mode:");
   getch();

   /* return to graphics mode */
   setgraphmode(getgraphmode());

   /* output a message */
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   outtextxy(x, y, "We're back in graphics mode.");
   outtextxy(x, y+textheight("W"), "Press any key to halt:");

   /* clean up */
   getch();
   closegraph();
   return 0;
}

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