C语言库函数大全及应用实例十二

原文:C语言库函数大全及应用实例十二

                                         [编程资料]C语言库函数大全及应用实例十二

---

函数名: setrgbpalette
功 能: 定义IBM8514图形卡的颜色
用 法: void far setrgbpalette(int colornum, int red, int green, int blue);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

int main(void)
{
/* select a driver and mode that supports the use */
/* of the setrgbpalette function. */
int gdriver = VGA, gmode = VGAHI, errorcode;
struct palettetype pal;
int i, ht, y, xmax;

/* 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 */
}

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

/* create gray scale */
for (i=0; i
setrgbpalette(pal.colors[i], i*4, i*4, i*4);

/* display the gray scale */
ht = getmaxy() / 16;
xmax = getmaxx();
y = 0;
for (i=0; i
{
setfillstyle(SOLID_FILL, i);
bar(0, y, xmax, y+ht);
y += ht;
}

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

函数名: settextjustify
功 能: 为图形函数设置文本的对齐方式
用 法: void far settextjustify(int horiz, int vert);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

/* function prototype */
void xat(int x, int y);

/* horizontal text justification settings */
char *hjust[] = { "LEFT_TEXT",
"CENTER_TEXT",
"RIGHT_TEXT"
};

/* vertical text justification settings */
char *vjust[] = { "LEFT_TEXT",
"CENTER_TEXT",
"RIGHT_TEXT"
};

int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int midx, midy, hj, vj;
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 */
}

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

/* loop through text justifications */
for (hj=LEFT_TEXT; hj<=RIGHT_TEXT; hj++)
for (vj=LEFT_TEXT; vj<=RIGHT_TEXT; vj++)
{
cleardevice();
/* set the text justification */
settextjustify(hj, vj);

/* create a message string */
sprintf(msg, "%s %s", hjust[hj], vjust[vj]);

/* create cross hairs on the screen */
xat(midx, midy);

/* output the message */
outtextxy(midx, midy, msg);
getch();
}

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

/* draw an "x" at (x, y) */
void xat(int x, int y)
{
line(x-4, y, x+4, y);
line(x, y-4, x, y+4);
}

函数名: settextstyle
功 能: 为图形输出设置当前的文本属性
用 法: void far settextstyle (int font, int direction, char size);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

/* the names of the text styles supported */
char *fname[] = { "DEFAULT font",
"TRIPLEX font",
"***ALL font",
"SANS SERIF font",
"GOTHIC font"
};

int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int style, midx, midy;
int size = 1;

/* 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;

settextjustify(CENTER_TEXT, CENTER_TEXT);

/* loop through the available text styles */
for (style=DEFAULT_FONT; style<=GOTHIC_FONT; style++)
{
cleardevice();
if (style == TRIPLEX_FONT)
size = 4;

/* select the text style */
settextstyle(style, HORIZ_DIR, size);

/* output a message */
outtextxy(midx, midy, fname[style]);
getch();
}

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

函数名: settextstyle
功 能: 为图形输出设置当前的文本属性
用 法: void far settextstyle (int font, int direction, char size);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

/* the names of the text styles supported */
char *fname[] = { "DEFAULT font",
"TRIPLEX font",
"***ALL font",
"SANS SERIF font",
"GOTHIC font"
};

int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int style, midx, midy;
int size = 1;

/* 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;

settextjustify(CENTER_TEXT, CENTER_TEXT);

/* loop through the available text styles */
for (style=DEFAULT_FONT; style<=GOTHIC_FONT; style++)
{
cleardevice();
if (style == TRIPLEX_FONT)
size = 4;

/* select the text style */
settextstyle(style, HORIZ_DIR, size);

/* output a message */
outtextxy(midx, midy, fname[style]);
getch();
}

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

函数名: settime
功 能: 设置系统时间
用 法: void settime(struct time *timep);
程序例:

＃i nclude
＃i nclude

int main(void)
{
struct time t;

gettime(&t);
printf("The current minute is: %d\n", t.ti_min);
printf("The current hour is: %d\n", t.ti_hour);
printf("The current hundredth of a second is: %d\n", t.ti_hund);
printf("The current second is: %d\n", t.ti_sec);

/* Add one to the minutes struct element and then call settime */
t.ti_min++;
settime(&t);

return 0;
}

函数名: setusercharsize
功 能: 为矢量字体改变字符宽度和高度
用 法: void far setusercharsize(int multx, int dirx, int multy, int diry);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

int main(void)
{
/* request autodetection */
int gdriver = DETECT, gmode, errorcode;

/* 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 */
}

/* select a text style */
settextstyle(TRIPLEX_FONT, HORIZ_DIR, 4);

/* move to the text starting position */
moveto(0, getmaxy() / 2);

/* output some normal text */
outtext("Norm ");

/* make the text 1/3 the normal width */
setusercharsize(1, 3, 1, 1);
outtext("Short ");

/* make the text 3 times normal width */
setusercharsize(3, 1, 1, 1);
outtext("Wide");

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

函数名: setvbuf
功 能: 把缓冲区与流相关
用 法: int setvbuf(FILE *stream, char *buf, int type, unsigned size);
程序例:

＃i nclude

int main(void)
{
FILE *input, *output;
char bufr[512];

input = fopen("file.in", "r+b");
output = fopen("file.out", "w");

/* set up input stream for minimal disk access,
using our own character buffer */
if (setvbuf(input, bufr, _IOFBF, 512) != 0)
printf("failed to set up buffer for input file\n");
else
printf("buffer set up for input file\n");

/* set up output stream for line buffering using space that
will be obtained through an indirect call to malloc */
if (setvbuf(output, NULL, _IOLBF, 132) != 0)
printf("failed to set up buffer for output file\n");
else
printf("buffer set up for output file\n");

/* perform file I/O here */

/* close files */
fclose(input);
fclose(output);
return 0;
}

函数名: setvect
功 能: 设置中断矢量入口
用 法: void setvect(int intr_num, void interrupt(*isr)());
程序例:

/***NOTE:
This is an interrupt service routine. You can NOT compile this
program with Test Stack Overflow turned on and get an executable
file which will operate correctly. */

＃i nclude
＃i nclude
＃i nclude

#define INTR 0X1C /* The clock tick interrupt */

void interrupt ( *oldhandler)(void);

int count=0;

void interrupt handler(void)
{
/* increase the global counter */
count++;

/* call the old routine */
oldhandler();
}

int main(void)
{
/* save the old interrupt vector */
oldhandler = getvect(INTR);

/* install the new interrupt handler */
setvect(INTR, handler);

/* loop until the counter exceeds 20 */
while (count < 20)
printf("count is %d\n",count);

/* reset the old interrupt handler */
setvect(INTR, oldhandler);

return 0;
}

函数名: setverify
功 能: 设置验证状态
用 法: void setverify(int value);
程序例:

＃i nclude
＃i nclude
＃i nclude

int main(void)
{
int verify_flag;

printf("Enter 0 to set verify flag off\n");
printf("Enter 1 to set verify flag on\n");

verify_flag = getch() - 0;

setverify(verify_flag);

if (getverify())
printf("DOS verify flag is on\n");
else
printf("DOS verify flag is off\n");

return 0;
}

函数名: setviewport
功 能: 为图形输出设置当前视口
用 法: void far setviewport(int left, int top, int right,
int bottom, int clipflag);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

#define CLIP_ON 1 /* activates clipping in viewport */

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

/* 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 */
}

setcolor(getmaxcolor());

/* message in default full-screen viewport */
outtextxy(0, 0, "* <-- (0, 0) in default viewport");

/* create a smaller viewport */
setviewport(50, 50, getmaxx()-50, getmaxy()-50, CLIP_ON);

/* display some text */
outtextxy(0, 0, "* <-- (0, 0) in smaller viewport");

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

函数名: setvisualpage
功 能: 设置可见图形页号
用 法: void far setvisualpage(int pagenum);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

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: setwritemode
功 能: 设置图形方式下画线的输出模式
用 法: void far setwritemode(int mode);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude

int main()
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int xmax, ymax;

/* 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 */
}

xmax = getmaxx();
ymax = getmaxy();

/* select XOR drawing mode */
setwritemode(XOR_PUT);

/* draw a line */
line(0, 0, xmax, ymax);
getch();

/* erase the line by drawing over it */
line(0, 0, xmax, ymax);
getch();

/* select overwrite drawing mode */
setwritemode(COPY_PUT);

/* draw a line */
line(0, 0, xmax, ymax);

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

函数名: signal
功 能: 设置某一信号的对应动作
用 法: int signal(int sig, sigfun fname);
程序例:

/* This example installs a signal handler routine for SIGFPE,
catches an integer overflow condition, makes an adjustment
to AX register, and returns. This example program MAY cause
your computer to crash, and will produce runtime errors
depending on which memory model is used.
*/

#pragma inline
＃i nclude
＃i nclude

void Catcher(int sig, int type, int *reglist)
{
printf("Caught it!\n");
*(reglist + 8) = 3; /* make return AX = 3 */
}

int main(void)
{
signal(SIGFPE, Catcher);
asm mov ax,07FFFH /* AX = 32767 */
asm inc ax /* cause overflow */
asm into /* activate handler */

/* The handler set AX to 3 on return. If that hadn't happened,
there would have been another exception when the next 'into'
was executed after the 'dec' instruction. */
asm dec ax /* no overflow now */
asm into /* doesn't activate */
return 0;
}

函数名: sin
功 能: 正弦函数
用 法: double sin(double x);
程序例:

＃i nclude
＃i nclude

int main(void)
{
double result, x = 0.5;

result = sin(x);
printf("The sin() of %lf is %lf\n", x, result);
return 0;
}

函数名: sinh
功 能: 双曲正弦函数
用 法: double sinh(double x);
程序例:

＃i nclude
＃i nclude

int main(void)
{
double result, x = 0.5;

result = sinh(x);
printf("The hyperbolic sin() of %lf is %lf\n", x, result);
return 0;
}

函数名: sleep
功 能: 执行挂起一段时间
用 法: unsigned sleep(unsigned seconds);
程序例:

＃i nclude
＃i nclude

int main(void)
{
int i;

for (i=1; i<5; i++)
{
printf("Sleeping for %d seconds\n", i);
sleep(i);
}
return 0;
}

函数名: sopen
功 能: 打开一共享文件
用 法: int sopen(char *pathname, int access, int shflag, int permiss);
程序例:

＃i nclude
＃i nclude
＃i nclude
＃i nclude
＃i nclude
＃i nclude

int main(void)
{
int handle;
int status;

handle = sopen("c:\\autoexec.bat", O_RDONLY, SH_DENYNO, S_IREAD);

if (!handle)
{
printf("sopen failed\n");
exit(1);
}

status = access("c:\\autoexec.bat", 6);
if (status == 0)
printf("read/write access allowed\n");
else
printf("read/write access not allowed\n");

close(handle);
return 0;
}

函数名: sound
功 能: 以指定频率打开PC扬声器
用 法: void sound(unsigned frequency);
程序例:

/* Emits a 7-Hz tone for 10 seconds.
Your PC may not be able to emit a 7-Hz tone. */
＃i nclude

int main(void)
{
sound(7);
delay(10000);
nosound();
return 0;
}

函数名: spawnl
功 能: 创建并运行子程序
用 法: int spawnl(int mode, char *pathname, char *arg0,
arg1, ... argn, NULL);
程序例:

＃i nclude
＃i nclude
＃i nclude

int main(void)
{
int result;

clrscr();
result = spawnl(P_WAIT, "tcc.exe", NULL);
if (result == -1)
{
perror("Error from spawnl");
exit(1);
}
return 0;
}

函数名: spawnle
功 能: 创建并运行子程序
用 法: int spawnle(int mode, char *pathname, char *arg0,
arg1,..., argn, NULL);
程序例:

/* spawnle() example */

＃i nclude
＃i nclude
＃i nclude

int main(void)
{
int result;

clrscr();
result = spawnle(P_WAIT, "tcc.exe", NULL, NULL);
if (result == -1)
{
perror("Error from spawnle");
exit(1);
}
return 0;
}

函数名: sprintf
功 能: 送格式化输出到字符串中
用 法: int sprintf(char *string, char *farmat [,argument,...]);
程序例:

＃i nclude
＃i nclude

int main(void)
{
char buffer[80];

sprintf(buffer, "An approximation of Pi is %f\n", M_PI);
puts(buffer);
return 0;
}

函数名: sqrt
功 能: 计算平方根
用 法: double sqrt(double x);
程序例:

＃i nclude
＃i nclude

int main(void)
{
double x = 4.0, result;

result = sqrt(x);
printf("The square root of %lf is %lf\n", x, result);
return 0;
}

函数名: srand
功 能: 初始化随机数发生器
用 法: void srand(unsigned seed);
程序例:

＃i nclude
＃i nclude
＃i nclude

int main(void)
{
int i;
time_t t;

srand((unsigned) time(&t));
printf("Ten random numbers from 0 to 99\n\n");
for(i=0; i<10; i++)
printf("%d\n", rand() % 100);
return 0;
}

函数名: sscanf
功 能: 执行从字符串中的格式化输入
用 法: int sscanf(char *string, char *format[,argument,...]);
程序例:

＃i nclude
＃i nclude

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
{
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
printf("%4d | %-20s | %5d | %15.2lf\n",
loop + 1,
entry[loop].name,
entry[loop].age,
entry[loop].salary);
printf("-----------------------------------------------------\n");
return 0;
}