c语言函数库哪里keyk [精品]C语言库函数(字母G-K)-教案.doc

[精品]C语言库函数(字母G-K)-教案

C语言库函数(字母G-K)- -

??????????????????????????????????????

(G类字母) - 1

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 */ }

函数名: getarccoords 功 能: 取得最后一次调用arc的坐标 用 法: void far getarccoords(struct arccoordstype far *arccoords); 程序例:

#include #include #include #include

int main(void) { /* request auto detection */ int gdriver = DETECT, gmode, errorcode; struct arccoordstype arcinfo; int midx, midy; int stangle = 45, endangle = 270; char sstr[80], estr[80];

/* initialize graphics and local variables */ initgraph(&gdriver, &gmode, "");

/* read result of initialization */ errorcode = graphresult(); /* an error occurred */ if (errorcode != grOk) { printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); /* terminate with an error code */ exit(1); }

m