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 */ }