[C语言]计算圆周率(Pi-X)

 1 #include <stdio.h>
 2 int main(){
 3     const ARRSIZE=1010, DISPCNT=1000; //定义数组大小，显示位数
 4     //const ARRSIZE=10100, DISPCNT=10000;
 5     char x[ARRSIZE], z[ARRSIZE]; //x[0] x[1] . x[2] x[3] x[4] .... x[ARRSIZE-1]
 6     int a=1, b=3, c, d, Run=1, Cnt=0,i;
 7     for (i=0;i<ARRSIZE;i++){
 8         x[i]=0;z[i]=0;
 9     }
10     //memset(x,0,ARRSIZE);
11     //memset(z,0,ARRSIZE);
12     x[1] = 2;
13     z[1] = 2;
14     while(Run && (++Cnt<200000000)){
15     //z*=a;
16     d = 0;
17     for(i=ARRSIZE-1; i>0; i--)
18     {
19         c = z[i]*a + d;
20         z[i] = c % 10;
21         d = c / 10;
22     }
23     //z/=b;
24     d = 0;
25     for(i=0; i<ARRSIZE; i++){
26         c = z[i]+d*10;
27         z[i] = c / b;
28         d = c % b;
29     }
30     //x+=z;
31     Run = 0;
32     for(i=ARRSIZE-1; i>0; i--){
33         c = x[i] + z[i];
34         x[i] = c%10;
35         x[i-1] += c/10;
36         Run |= z[i];
37     }
38     a++;
39     b+=2;
40     //printf("计算了 %d 次\n",Cnt);
41     }
42     printf("计算了 %d 次\r\n",Cnt);
43     printf("Pi=%d%d.\r\n", x[0],x[1]);
44     for(i=0; i<DISPCNT; i++){
45         if(i && ((i%100)==0))
46         printf("\r\n");
47         printf("%d",(int)x[i+2]);
48     }
49 }