C語言函數(shù)大全(g開頭)

函數(shù)名: gcvt
    功 能: 把浮點數(shù)轉換成字符串
    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);
    }
    函數(shù)名: geninterrupt
    功 能: 產(chǎn)生一個軟中斷
    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 */
    }