|
Turbo C 2.0、Borland C++库函数及用例(35) 用 法: long ftell(FILE *stream);
程序例:#include <stdio.h>int main(void)
{
FILE *stream; stream = fopen("MYFILE.TXT", "w+");
fprintf(stream, "This is a test"); printf("The file pointer is at byte \
%ld\n", ftell(stream));
fclose(stream);
return 0;
}
函数名: fwrite
功 能: 写内容到流中
用 法: int fwrite( void *ptr, int size, int nitems,
FILE *stream );
程序例:#include <stdio.h>struct mystruct
{
int i;
char ch;
};int main(void)
{
FILE *stream;
struct mystruct s; if ((stream = fopen("TEST.$$$", "wb")) == NULL)
/* open file TEST.$$$ */
{
fprintf(stderr, "Cannot open output file.\n");
return 1;
}
s.i = 0;
s.ch = 'A'; fwrite(&s, sizeof(s), 1, stream);
/* write struct s to file */
fclose(stream); /* close file */
return 0;
}字母Ｇ开头函数函数名: 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 <stdlib.h>
#include <stdio.h>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: 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 <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>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)
|
