C语言经典算法100例(4)

#include "stdio.h"

main()

{

int a,b;

a=077;

b=a|3;

printf("\40: The a & b(decimal) is %d \n",b);

b|=7;

printf("\40: The a & b(decimal) is %d \n",b);

}

题目：学习使用按位异或 ^ 。　　　

___________________________________________________________________程序分析：0^0=0; 0^1=1; 1^0=1; 1^1=0

___________________________________________________________________程序源代码：

#include "stdio.h"

main()

{

int a,b;

a=077;

b=a^3;

printf("\40: The a & b(decimal) is %d \n",b);

b^=7;

printf("\40: The a & b(decimal) is %d \n",b);

}

题目：取一个整数a从右端开始的4～7位。

___________________________________________________________________程序分析：可以这样考虑：

(1)先使a右移4位。

(2)设置一个低4位全为1,其余全为0的数。可用~(~0<<4)

(3)将上面二者进行&运算。

C语言经典算法100例

___________________________________________________________________程序源代码：

main()

{

unsigned a,b,c,d;

scanf("%o",&a);

b=a>>4;

c=~(~0<<4);

d=b&c;

printf("%o\n%o\n",a,d);

}

题目：学习使用按位取反~。　　　

___________________________________________________________________程序分析：~0=1; ~1=0;

___________________________________________________________________程序源代码：

#include "stdio.h"

main()

{

int a,b;

a=234;

b=~a;

printf("\40: The a's 1 complement(decimal) is %d \n",b);

a=~a;

printf("\40: The a's 1 complement(hexidecimal) is %x \n",a);}

题目：画图，学用circle画圆形。

___________________________________________________________________程序源代码：

/*circle*/

#include "graphics.h"

main()

{

int driver,mode,i;

float j=1,k=1;

driver=VGA;mode=VGAHI;

initgraph(&driver,&mode,"");

setbkcolor(YELLOW);

for(i=0;i<=25;i++)

{

setcolor(8);

circle(310,250,k);

k=k+j;

j=j+0.3;

}

}

题目：画图，学用line画直线。

___________________________________________________________________　　　　　

程序源代码：

#include "graphics.h"

main()

{

int driver,mode,i;

float x0,y0,y1,x1;

float j=12,k;

driver=VGA;mode=VGAHI;

C语言经典算法100例

initgraph(&driver,&mode,"");

setbkcolor(GREEN);

x0=263;y0=263;y1=275;x1=275;

for(i=0;i<=18;i++)

{

setcolor(5);

line(x0,y0,x0,y1);

x0=x0-5;

y0=y0-5;

x1=x1+5;

y1=y1+5;

j=j+10;

}

x0=263;y1=275;y0=263;

for(i=0;i<=20;i++)

{

setcolor(5);

line(x0,y0,x0,y1);

x0=x0+5;

y0=y0+5;

y1=y1-5;

}

}

题目：画图，学用rectangle画方形。　　　

___________________________________________________________________　

程序分析：利用for循环控制100-999个数，每个数分解出个位，十位，百位。___________________________________________________________________　

程序源代码：

#include "graphics.h"

main()

{

int x0,y0,y1,x1,driver,mode,i;

driver=VGA;mode=VGAHI;

initgraph(&driver,&mode,"");

setbkcolor(YELLOW);

x0=263;y0=263;y1=275;x1=275;

for(i=0;i<=18;i++)

{

setcolor(1);

rectangle(x0,y0,x1,y1);

x0=x0-5;

y0=y0-5;

x1=x1+5;

y1=y1+5;

}

settextstyle(DEFAULT_FONT,HORIZ_DIR,2);

outtextxy(150,40,"How beautiful it is!");

line(130,60,480,60);

setcolor(2);

circle(269,269,137);

}