函数名: ecvt

功 能: 把一个浮点数转换为字符串

用 法: char ecvt(double value, int ndigit, int *decpt, int *sign);

程序例:

#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
int main(void)
{
char *string;
double value;
int dec, sign;
int ndig = 10;
clrscr();
value = 9.876;
string = ecvt(value, ndig, &dec, &sign);
printf("string = %s dec = %d \
sign = %d\n", string, dec, sign);
value = -123.45;
ndig= 15;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d sign = %d\n",
string, dec, sign); value = 0.6789e5; /* scientific
notation */
ndig = 5;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d\
sign = %d\n", string, dec, sign);
return 0;
}

函数名: ellipse

功 能: 画一椭圆

用 法: void far ellipse(int x, int y, int stangle, int endangle,

    int xradius, int yradius); 

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;
int stangle = 0, endangle = 360;
int xradius = 100, yradius = 50;
/* initialize graphics, 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 ellipse */
ellipse(midx, midy, stangle, endangle,
xradius, yradius);
/* clean up */
getch();
closegraph();
return 0;
}

函数名: enable

功 能: 开放硬件中断

用 法: void enable(void);

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.
*/
#include <stdio.h>
#include <dos.h>
#include <conio.h>
/* The clock tick interrupt */
#define INTR 0X1C
void interrupt ( *oldhandler)(void);
int count=0;
void interrupt handler(void)
{
/*
disable interrupts during the handling of the interrupt
*/
disable();
/* increase the global counter */
count++;
/*
re enable interrupts at the end of the handler
*/
enable();
/* 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: eof

功 能: 检測文件结束

用 法: int eof(int *handle);

程序例:

#include <sys\stat.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>
int main(void)
{
int handle;
char msg[] = "This is a test";
char ch;
/* create a file */
handle = open("DUMMY.FIL",
O_CREAT | O_RDWR,
S_IREAD | S_IWRITE);
/* write some data to the file */
write(handle, msg, strlen(msg));
/* seek to the beginning of the file */
lseek(handle, 0L, SEEK_SET);
/*
reads chars from the file until hit EOF
*/
do
{
read(handle, &ch, 1);
printf("%c", ch);
} while (!eof(handle));
close(handle);
return 0;
}

函数名: exec...

功 能: 装入并执行其他程序的函数

用 法: int execl(char *pathname, char *arg0, arg1, ..., argn, NULL);

 int execle(char *pathname, char *arg0, arg1, ..., argn, NULL,
char *envp[]);
int execlp(char *pathname, char *arg0, arg1, .., NULL);
int execple(char *pathname, char *arg0, arg1, ..., NULL,
char *envp[]);
int execv(char *pathname, char *argv[]);
int execve(char *pathname, char *argv[], char *envp[]);
int execvp(char *pathname, char *argv[]);
int execvpe(char *pathname, char *argv[], char *envp[]);

程序例:

/* execv example */
#include <process.h>
#include <stdio.h>
#include <errno.h>
void main(int argc, char *argv[])
{
int i;
printf("Command line arguments:\n");
for (i=0; i<argc; i++)
printf("[%2d] : %s\n", i, argv[i]);
printf("About to exec child with arg1 arg2 ...\n");
execv("CHILD.EXE", argv);
perror("exec error");
exit(1);
}

函数名: exit

功 能: 终止程序

用 法: void exit(int status);

程序例:

#include <stdlib.h>
#include <conio.h>
#include <stdio.h>
int main(void)
{
int status;
printf("Enter either 1 or 2\n");
status = getch();
/* Sets DOS errorlevel */
exit(status - '0');
/* Note: this line is never reached */
return 0;
}

函数名: exp

功 能: 指数函数

用 法: double exp(double x);

程序例:

#include <stdio.h>
#include <math.h>
int main(void)
{
double result;
double x = 4.0;
result = exp(x);
printf("'e' raised to the power \
of %lf (e ^ %lf) = %lf\n",
x, x, result);
return 0;
}

书画小说软件 制作更满意的读、更舒心的写、更轻松的公布



最全古典小说网 由本软件公布所得

最新文章

  1. LruCache详解之 Android 内存优化
  2. Linux基础命令总结
  3. sqlserver临时启用和关闭约束
  4. Objects and Data Structures
  5. java实现url转码、解码
  6. Android环境结构--安装Eclipse错
  7. JSON 和 JSONP 两兄弟
  8. async await promise
  9. Android的ListView异步加载图片时,错位、重复、闪烁问题的分析及解决方法
  10. BZOJ_1098_[POI2007]办公楼biu_链表优化BFS
  11. C# 远程获取图片二进制
  12. java包
  13. PHP输出缓存ob系列函数
  14. DFS服务待书写
  15. 使用python快速搭建web服务器
  16. [ 原创 ] git使用技巧
  17. Spring学习(七)——开发Web Service的几种方式
  18. thusc2018酱油记
  19. 仿阿里云后台管理界面模板html源码——后台
  20. poj 1141 Brackets Sequence ( 区间dp+输出方案 )

热门文章

  1. javascript工具--控制台详解
  2. ZBrush实用插件ZAppLink简介
  3. CentOS 6.9 CentOS 7.4 自动安装系统 kickstart
  4. JDOJ 2785: 商之和 数论分块
  5. NOIp2018模拟赛四十五~??
  6. C语言的常用printf打印占位符%d, %u, %f, %s, %c, %o, %x
  7. ES6学习笔记(二十)Module 的加载实现
  8. BZOJ 3881 [COCI2015]Divljak (Trie图+Fail树+树链的并+树状数组维护dfs序)
  9. 一句话木马和中国菜刀的结合拿webshell
  10. WPF 内存释放