（1） 用C语言生成DXF文件#includestdio.h#includeconio.hFILE *fp;void hsec(),endsec();void line();void arc();void text();main() char a8=KEY40; clrscr(); fp=fopen(d:key.dxf,w); if(fp=NULL) printf(cant openn); exit(1); hsec(fp); line(fp,20.0,20.0,50.0,20.0); line(fp,20.0,30.0,50.0,30.0); arc(fp,20.0,25.0,5.0,90.0,270.0); arc(fp,50.0,25.0,5.0,-90.0,90.0); text(fp,30.0,45.0,3.5,0.0,0.0,a); endsec(fp); fclose(fp);/接口子程序/void hsec(FILE *fp) fprintf(fp,0nSECTIONn2nENTITIESn);/*n为换行符*/ void line(FILE *fp,double x1,double y1,double x2,double y2) fprintf(fp,0nlinen8nAn10n);/A为层名 fprintf(fp,%9.4fn,x1); fprintf(fp,20n); fprintf(fp,%9.4fn,y1); fprintf(fp,11n); fprintf(fp,%9.4fn,x2); fprintf(fp,21n); fprintf(fp,%9.4fn,y2); void arc(FILE *fp,double x,double y,double r,double sang,double eang) fprintf(fp,0narcn8nAn10n);/A为层名 fprintf(fp,%9.4fn,x); fprintf(fp,20n); fprintf(fp,%9.4fn,y); fprintf(fp,40n); fprintf(fp,%9.4fn,r); fprintf(fp,50n); fprintf(fp,%9.4fn,sang); fprintf(fp,51n); fprintf(fp,%9.4fn,eang); void cirlce(FILE *fp,double x,double y,double r) fprintf(fp,0ncirclen8nAn10n);/A为层名 fprintf(fp,%9.4fn,x); fprintf(fp,20n); fprintf(fp,%9.4fn,y); fprintf(fp,40n); fprintf(fp,%9.4fn,r);void text(FILE *fp,double x,double y,double h,double rota,double ang,char *tex) fprintf(fp,0ntextn8nAn10n);/A为层名 fprintf(fp,%9.4fn,x); fprintf(fp,20n); fprintf(fp,%9.4fn,y); fprintf(fp,40n); fprintf(fp,%9.4fn,h); fprintf(fp,1n); fprintf(fp,%sn,tex); fprintf(fp,50n); fprintf(fp,%9.4fn,rota); fprintf(fp,51n); fprintf(fp,%9.4fn,ang);void endsec(FILE *fp) fprintf(fp,0nENDSECn0nEOFn); 3