用C语言编程绘制函数的图像源程序.docx

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1、#include#include#includefloata,b,c,xmin,xmax,max;/*定义全局变量*/voidmenu(){printf("************************************WELCOME*************************************");printf("1.输入参数");printf("2.输入x的范围");printf("3.画函数图像");printf("4.退出");printf("*

2、*******************************************************************************");}fun1(){printf("输入a,b,c");scanf("%f,%f,%f",&a,&b,&c);/*输入系数a,b,c*/}fun2()/*输入x范围*/{printf("输入xmin,xmax");scanf("%f,%f",&xmin,&xmax);}funmax()/*求出x轴最大范围*/{floatm,n;if(xmin<0)m=-xmin;elsem=xmin;if(

3、xmax<0)n=-xmax;elsen=xmax;if(m>=n)max=m;elsemax=n;}floatfunx(floatmax_x)/*求出x轴对应系数*/{return(max_x/2/max);}floatfuny(floatmax_y)/*求出y轴对应系数*/{floatd;d=max_y/2/(a*max*max+b*max+c);if(d>0.6)d=0.6;if(d<0.0026)d=0.0026;return(d);}fun3(){intmax_x,max_y;intgraphdriver=DETECT,graphmode;float

4、x1,y1,x2,y2,x,coe_x,coe_y;initgraph(&graphdriver,&graphmode,"");/*图形初始化*/cleardevice();/*清屏*/max_x=getmaxx();/*求出屏幕最大横坐标*/max_y=getmaxy();/*求出屏幕最大横坐标*/funmax();coe_x=funx(max_x);coe_y=funy(max_y);line(0,240,640,240);/*画直线*/line(320,0,320,480);line(640,240,635,235);line(640,240,635,2

5、45);line(320,0,315,5);line(320,0,325,5);outtextxy(320,240,"(0,0)");/*在固定点输出字符串*/outtextxy(620,240,"x");outtextxy(320,10,"y");x1=max_x/2+xmin*coe_x,y1=max_y/2-(a*xmin*coe_x*xmin*coe_x+b*xmin*coe_x+c)*coe_y;moveto((int)x1,(int)y1);for(x=xmin*coe_x;x<=xmax*coe_x;x++){x2=max_x/2+x,y2=ma

6、x_y/2-(a*x*x+b*x+c)*coe_y;lineto((int)x2,(int)y2);}getch();closegraph();/*关闭图形函数*/}main(){intn;menu();while(1){scanf("%d",&n);switch(n){case1:fun1();break;case2:fun2();break;case3:fun3();break;case4:exit(0);default:printf("error");}}}