【程序64】
题目：利用ellipse and rectangle 画图。
1.程序分析：
2.程序源代码：
#include "stdio.h"
#include "graphics.h"
#include "conio.h"
main()
{
int driver=VGA,mode=VGAHI;
int i,num=15,top=50;
int left=20,right=50;
initgraph(&driver,&mode,"");
for(i=0;i<num;i++)
{
ellipse(250,250,0,360,right,left);
ellipse(250,250,0,360,20,top);
rectangle(20-2*i,20-2*i,10*(i+2),10*(i+2));
right+=5;
left+=5;
top+=10;
}
getch();
}
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【程序65】
题目：一个最优美的图案。
1.程序分析：
2.程序源代码：
#include "graphics.h"
#include "math.h"
#include "dos.h"
#include "conio.h"
#include "stdlib.h"
#include "stdio.h"
#include "stdarg.h"
#define MAXPTS 15
#define PI 3.1415926
struct PTS {
int x,y;
};
double AspectRatio=0.85;
void LineToDemo(void)
{
struct viewporttype vp;
struct PTS points[MAXPTS];
int i, j, h, w, xcenter, ycenter;
int radius, angle, step;
double rads;
printf(" MoveTo / LineTo Demonstration" );
getviewsettings( &vp );
h = vp.bottom - vp.top;
w = vp.right - vp.left;
xcenter = w / 2; /* Determine the center of circle */
ycenter = h / 2;
radius = (h - 30) / (AspectRatio * 2);
step = 360 / MAXPTS; /* Determine # of increments */
angle = 0; /* Begin at zero degrees */
for( i=0 ; i<MAXPTS ; ++i ){ /* Determine circle intercepts */
rads = (double)angle * PI / 180.0; /* Convert angle to radians */
points.x = xcenter + (int)( cos(rads) * radius );
points.y = ycenter - (int)( sin(rads) * radius * AspectRatio );
angle += step; /* Move to next increment */
}
circle( xcenter, ycenter, radius ); /* Draw bounding circle */
for( i=0 ; i<MAXPTS ; ++i ){ /* Draw the cords to the circle */
for( j=i ; j<MAXPTS ; ++j ){ /* For each remaining intersect */
moveto(points.x, points.y); /* Move to beginning of cord */
lineto(points[j].x, points[j].y); /* Draw the cord */
} } }
main()
{int driver,mode;
driver=CGA;mode=CGAC0;
initgraph(&driver,&mode,"");
setcolor(3);
setbkcolor(GREEN);
LineToDemo();}
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【程序66】
题目：输入3个数a,b,c，按大小顺序输出。
1.程序分析：利用指针方法。
2.程序源代码：
/*pointer*/
main()
{
int n1,n2,n3;
int *pointer1,*pointer2,*pointer3;
printf("please input 3 number:n1,n2,n3:");
scanf("%d,%d,%d",&n1,&n2,&n3);
pointer1=&n1;
pointer2=&n2;
pointer3=&n3;
if(n1>n2) swap(pointer1,pointer2);
if(n1>n3) swap(pointer1,pointer3);
if(n2>n3) swap(pointer2,pointer3);
printf("the sorted numbers are:%d,%d,%d\n",n1,n2,n3);
}
swap(p1,p2)
int *p1,*p2;
{int p;
p=*p1;*p1=*p2;*p2=p;
}
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【程序67】
题目：输入数组，最大的与第一个元素交换，最小的与最后一个元素交换，输出数组。
1.程序分析：谭浩强的书中答案有问题。
2.程序源代码：
main()
{
int number[10];
input(number);
max_min(number);
output(number);
}
input(number)
int number[10];
{int i;
for(i=0;i<9;i++)
scanf("%d,",&number);
scanf("%d",&number[9]);
}
max_min(array)
int array[10];
{int *max,*min,k,l;
int *p,*arr_end;
arr_end=array+10;
max=min=array;
for(p=array+1;p<arr_end;p++)
if(*p>*max) max=p;
else if(*p<*min) min=p;
k=*max;
l=*min;
*p=array[0];array[0]=l;l=*p;
*p=array[9];array[9]=k;k=*p;
return;
}
output(array)
int array[10];
{ int *p;
for(p=array;p<array+9;p++)
printf("%d,",*p);
printf("%d\n",array[9]);
}
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【程序68】
题目：有n个整数，使其前面各数顺序向后移m个位置，最后m个数变成最前面的m个数
1.程序分析：
2.程序源代码：
main()
{
int number[20],n,m,i;
printf("the total numbers is:");
scanf("%d",&n);
printf("back m:");
scanf("%d",&m);
for(i=0;i<n-1;i++)
scanf("%d,",&number);
scanf("%d",&number[n-1]);
move(number,n,m);
for(i=0;i<n-1;i++)
printf("%d,",number);
printf("%d",number[n-1]);
}
move(array,n,m)
int n,m,array[20];
{
int *p,array_end;
array_end=*(array+n-1);
for(p=array+n-1;p>array;p--)
*p=*(p-1);
*array=array_end;
m--;
if(m>0) move(array,n,m);
}
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