C语言函数大全(g开头)

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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\n", str);

/* a negative number */

num = -123.4567;

gcvt(num, sig, str);

printf("string = %s\n", str);

/* scientific notation */

num = 0.678e5;

gcvt(num, sig, str);

printf("string = %s\n", 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 */

}