标签：%. 函数 -- double C语言 int printf include

C语言函数大全

本篇介绍C语言函数大全中其他 c 开头的函数

1. cbrt，cbrtf，cbrtl

1.1 函数说明

函数声明	函数功能
double cbrt (double x)	计算 x 的立方根（double）
float cbrtf (float x)	计算 x 的立方根（float）
long double cbrtl (long double x)	计算 x 的立方根（long double）

1.2 演示示例

#include <stdio.h>
#include <math.h>

int main(void)
{
    double x = 8.0;
    float xf = 27.0;
    long double xL = 64.0;

    // 立方根
    printf("The cube root of the double value %.4lf is %.4lf\n", x, cbrt(x));
    printf("The cube root of the float value %.4f is %.4f\n", xf, cbrtf(xf));
    printf("The cube root of the long double value %.4Lf is %.4Lf", xL, cbrtl(xL));    

    return 0;
}

1.3 运行结果

2. ceil，ceilf，ceill

2.1 函数说明

函数声明	函数功能
double ceil (double x)	计算大于或等于x的最小整数（double）
float ceilf (float x)	计算大于或等于x的最小整数（float）
long double ceill (long double x)	计算大于或等于x的最小整数（long double）

2.2 演示示例

#include <stdio.h>
#include <math.h>

int main(void)
{
    double x = 2.3;
    float xf = 2.5;
    long double xL = 2.8;

    // 计算大于或等于x的最小整数
    printf("The minimum integer greater than or equal to the [x = %.4lf] is %.4lf\n", x, ceil(x));
    printf("The minimum integer greater than or equal to the [x = %.4f]  is %.4f\n", xf, ceilf(xf));
    printf("The minimum integer greater than or equal to the [x = %.4Lf] is %.4Lf", xL, ceill(xL));    
    return 0;
}

2.3 运行结果

3. copysign，copysignf，copysignl

3.1 函数说明

函数声明	函数功能
double copysign (double x, double y);	通过组合x的大小和y的符号生成一个值。（double） 例如，如果x为2.0，y为-1.0，则将生成值-2.0。
float copysignf (float x, float y);	通过组合x的大小和y的符号生成一个值。（float） 例如，如果x为2.0，y为-1.0，则将生成值-2.0。
long double copysignl (long double x, long double y);	通过组合x的大小和y的符号生成一个值。（long double） 例如，如果x为2.0，y为-1.0，则将生成值-2.0。

3.2 演示示例

#include <stdio.h>
#include <math.h>

int main(void)
{
    double x = 2.0, y = -1.0;
    float xf = 2.0, yf = -1.0;
    long double xL = 2.0, yL = -1.0;

    // 通过组合x的大小和y的符号生成一个值
    printf("The double value by combining the magnitude of [x = %.4lf] and the sign of [y = %.4lf] is %.4lf\n", x, y, copysign(x, y));
    printf("The float value by combining the magnitude of [x = %.4f] and the sign of [y = %.4f] is %.4f\n", xf, yf, copysignf(xf, yf));
    printf("The long double value by combining the magnitude of [x = %.4Lf] and the sign of [y = %.4Lf] is %.4Lf", xL, yL, copysignl(xL, yL));    
    return 0;
}

3.3 运行结果

4. chdir

4.1 函数说明

函数声明	函数功能
int chdir(const char *path);	更改当前的工作目录。如果成功返回 0，否则返回 -1

4.2 演示示例

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

#define MAXDIR 1000
char old_dir[MAXDIR];
char new_dir[MAXDIR];

int main()
{
    if (!getcwd(old_dir, MAXDIR)) // 获取当前的目录
    {
        perror("getcwd()");
        exit(1);
    }
    printf("Current directory is: %s\n", old_dir); 

    if (chdir("D:\\")) // 切换目录，成功返回0，失败返回-1
    {
        perror("chdir()");
        exit(1);
    }

    if (!getcwd(new_dir, MAXDIR))
    {
        perror("getcwd()");
        exit(1);
    }
    printf("Current directory is now: %s\n", new_dir);

    printf("\nChanging back to orignal directory: %s\n", old_dir);

    if (chdir(old_dir))
    {
        perror("chdir()");
        exit(1);
    }

    return 0;
}

4.3 运行结果

5. chmod

5.1 函数说明

函数声明	函数功能
int chmod( const char *filename, int pmode);	变更文件或目录的权限。如果改变成功返回0，否则返回-1

5.2 演示示例

5.3 运行结果

6. chsize

6.1 函数说明

函数声明	函数功能
int chsize(int handle, long size);	改变文件大小

6.2 演示示例

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>
int main()
{
   int fh, result;
   unsigned int nbytes = 2048;
   // 打开文件
   if((fh=open("temp.txt", _O_RDWR | _O_CREAT, _S_IREAD | _S_IWRITE))  != -1)
   {
      printf("File length before: %ld\n", filelength(fh)); // 获取文件大小
      if((result=chsize(fh, nbytes))== 0)
         printf("Size successfully changed\n");
      else
         printf("Problem in changing the size\n");
      printf("File length after:  %ld\n", filelength(fh));
      close(fh);
   }
   return 0;
}

6.3 运行结果

7. circle

7.1 函数说明

函数声明	函数功能
void circle(int x, int y, int radius);	在给定半径radius，以(x, y)为圆心画圆

7.2 演示示例

#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;
	int radius = 100;

	/* 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());

	/* draw the circle */
	circle(midx, midy, radius);

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

7.3 运行结果

8. cleardevice

8.1 函数说明

函数声明	函数功能
void cleardevice(void);	清除图形屏幕

8.2 演示示例

#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;

	/* 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());

	/* for centering screen messages */
	settextjustify(CENTER_TEXT, CENTER_TEXT);

	/* output a message to the screen */
	outtextxy(midx, midy, "press any key to clear the screen:");

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

	/* clear the screen */
	cleardevice();

	/* output another message */
	outtextxy(midx, midy, "press any key to quit:");

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

8.3 运行结果

9. clearerr

9.1 函数说明

函数声明	函数功能
void clearerr(FILE *stream);	复位错误标志，使用它可以使文件错误标志和文件结束标志置为 0。

9.2 演示示例

#include <stdio.h>

int main(void)
{
    FILE *fp;
    char ch;

    /* open a file for writing */
    fp = fopen("temp.txt", "w");

    /* force an error condition by attempting to read */
    ch = fgetc(fp);
    printf("%c\n",ch);

    int errorFlag = ferror(fp);
    printf("Error Flag : %d\n", errorFlag);
    if (errorFlag)
    {
        /* display an error message */
        printf("Error reading from temp.txt\n");

        /* reset the error and EOF indicators */
        clearerr(fp);
    }

    printf("Error Flag : %d", ferror(fp));

    fclose(fp);
    return 0;
}

9.3 运行结果

10. clearviewport

10.1 函数说明

函数声明	函数功能
void clearviewport();	清除图形视区

10.2 演示示例

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

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

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

	setcolor(getmaxcolor());
	ht = textheight("W");

	/* 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 messages */
	outtextxy(0, 0, "* <-- (0, 0) in smaller viewport");
	outtextxy(0, 2*ht, "Press any key to clear viewport:");

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

	/* clear the viewport */
	clearviewport();

	/* output another message */
	outtextxy(0, 0, "Press any key to quit:");

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

10.3 运行结果

11. close

11.1 函数说明

函数声明	函数功能
int close(int handle);	通过文件描述符handle，来关闭文件，成功返回0，出错返回-1

11.2 演示示例

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>

int main()
{
    int handle;
    char buf[11] = "0123456789";

    /* create a file containing 10 bytes */
    handle = open("temp.txt", _O_RDWR | _O_CREAT, _S_IREAD | _S_IWRITE);
    if (handle > -1)
    {
        write(handle, buf, strlen(buf));
        printf("Write successfully\n");
        /* close the file */
        close(handle);
        printf("Close File successfully");
    }
    else
    {
        printf("Error opening file\n");
    }
    return 0;
}

11.3 运行结果

12. clock

12.1 函数说明

函数声明	函数功能
long clock(void);	确定处理器调用某个进程或函数所用的时间

12.2 演示示例

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

int main(void)
{
    clock_t start, end;
    start = clock();
    printf("start = %ld\n", start);
    getchar();

    end = clock();
    printf("end = %ld\n", end);
    printf("The time was: %.3lfs\n", (double) (end - start) / CLK_TCK);

    return 0;
}

12.3 运行结果

13. closegraph

13.1 函数说明

函数声明	函数功能
void closegraph();	关闭图形系统

13.2 演示示例

#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 mode */
	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 a key to close the graphics system:");

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

	/* closes down the graphics system */
	closegraph();

	printf("We're now back in text mode.\n");
	printf("Press any key to halt:");
	getchar();
	return 0;
}

13.3 运行结果

14. cos，cosf，cosl

14.1 函数说明

函数声明	函数功能
double cos(double x);	计算x的余弦（double）
float cosf(float x);	计算x的余弦（float）
long double cosl(long double x);	计算x的余弦（long double）

14.2 演示示例

// Huazie
#include <stdio.h>
#include <math.h>

int main(void)
{
    double x = 1.0;
    double result = cos(x); // 余弦

    float xf = 1.0f;
    float resultf = cosf(xf);

    long double xL = 1.0;
    long double resultL = cosl(xL);

    printf("The cosine of %lf is %.16lf\n", x, result);
    printf("The cosine of %f is %.16f\n", xf, resultf);
    printf("The cosine of %Lf is %.16Lf\n", xL, resultL);

    return 0;
}

14.3 运行结果

15. cosh，coshf，coshl

15.1 函数说明

函数声明	函数功能
double cosh(double x);	计算x的双曲余弦（double）
float coshf(float x);	计算x的双曲余弦（float）
long double coshl(long double x);	计算x的双曲余弦（long double）

15.2 演示示例

// Huazie
#include <stdio.h>
#include <math.h>

int main(void)
{
    double x = 1.0;
    double result = cosh(x); // 双曲余弦

    float xf = 1.0f;
    float resultf = coshf(xf);

    long double xL = 1.0;
    long double resultL = coshl(xL);

    printf("The hyperbolic coshine of %lf is %.16lf\n", x, result);
    printf("The hyperbolic coshine of %f is %.16f\n", xf, resultf);
    printf("The hyperbolic coshine of %Lf is %.16Lf\n", xL, resultL);

    return 0;
}

15.3 运行结果

16. creat

16.1 函数说明

函数声明	函数功能
int creat (const char *filename, int mode);	创建一个新文件或重写一个已存在的文件

16.2 演示示例

#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>

int main(void)
{
   int handle;
   char buf[11] = "0123456789";

   handle = creat("temp1.txt", S_IREAD | S_IWRITE);

   printf("Create file successfully");

   /* write 10 bytes to the file */
   write(handle, buf, strlen(buf));

   /* close the file */
   close(handle);
   return 0;
}

16.3 运行结果

17. ctime

17.1 函数说明

函数声明	函数功能
char *ctime(const time_t *time);	把日期和时间转换为字符串

17.2 演示示例

#include <stdio.h>
#include <time.h>

int main(void)
{
    time_t t;
    time(&t);
    printf("Today's date and time: %s\n", ctime(&t));
    return 0;
}

17.3 运行结果

参考

1. [API Reference Document]

标签：%.,函数,--,double,C语言,int,printf,include
From： https://blog.51cto.com/huazie/6144367