C语言函数大全（g开头）

C语言函数大全（g开头）2010-01-29函数名: gcvt

功能: 把浮点数转换成字符串

用法: char *gcvt（double value, int ndigit, char *buf）;

程序例:

#include
#include
int main（void）
{
char str[25];
double num;
int sig = 5; /* significant digits */
/* a regular number */
num = 9.876;
gcvt（num, sig, str）;
printf（"string = %s
", str）;
/* a negative number */
num = -123.4567;
gcvt（num, sig, str）;
printf（"string = %s
", str）;
/* scientific notation */
num = 0.678e5;
gcvt（num, sig, str）;
printf（"string = %s
", str）;
return（0）;
}

函数名: geninterrupt

功能: 产生一个软中断

用法: void geninterrupt（int intr_num）;

程序例:

#include
#include
/* function prototype */
void writechar（char ch）;
int main（void）
{
clrscr（）;
gotoxy（80,25）;
writechar（"*"）;
getch（）;
return 0;
}
/*
outputs a character at the current cursor
position using the video BIOS to avoid the
scrolling of the screen when writing to
location （80,25）.
*/
void writechar（char ch）
{
struct text_info ti;
/* grab current text settings */
gettextinfo（&ti）;
/* interrupt 0x10 sub-function 9 */
_AH = 9;
/* character to be output */
_AL = ch;
_BH = 0; /* video page */
_BL = ti.attribute; /* video attribute */
_CX = 1; /* repetition factor */
geninterrupt（0x10）; /* output the char */
}