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
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
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
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
4.2 演示示例
#include <stdio.h>#include <stdlib.h>#include <dir.h>#define MAXDIR 1000char 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
5.2 演示示例
#include <sys\stat.h>#include <stdio.h>#include <io.h>void make_read_only(char *filename);int main(void){make_read_only("NOTEXIST.FIL");make_read_only("students.txt");return 0;}void make_read_only(char *filename){int stat;stat = chmod(filename, S_IREAD);if (stat)printf("Couldn't make %s read-only\n", filename);elseprintf("Made %s read-only\n", filename);}
5.3 运行结果
6. chsize
6.1 函数说明
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");elseprintf("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
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
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
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
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
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
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
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
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
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
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
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;}
