[C語言]計算圓周率(Pi-X)

Code:

#include <stdio.h>
int main(){
    const ARRSIZE=1010, DISPCNT=1000; //定義數組大小，顯示位數
    //const ARRSIZE=10100, DISPCNT=10000;
    char x[ARRSIZE], z[ARRSIZE]; //x[0] x[1] . x[2] x[3] x[4] .... x[ARRSIZE-1]
    int a=1, b=3, c, d, Run=1, Cnt=0,i;
    for (i=0;i<ARRSIZE;i++){
        x[i]=0;z[i]=0;
    }
    //memset(x,0,ARRSIZE);
    //memset(z,0,ARRSIZE);
    x[1] = 2;
    z[1] = 2;
    while(Run && (++Cnt<200000000)){
    //z*=a;
    d = 0;
    for(i=ARRSIZE-1; i>0; i--)
    {
        c = z[i]*a + d;
        z[i] = c % 10;
        d = c / 10;
    }
    //z/=b;
    d = 0;
    for(i=0; i<ARRSIZE; i++){
        c = z[i]+d*10;
        z[i] = c / b;
        d = c % b;
    }
    //x+=z;
    Run = 0;
    for(i=ARRSIZE-1; i>0; i--){
        c = x[i] + z[i];
        x[i] = c%10;
        x[i-1] += c/10;
        Run |= z[i];
    }
    a++;
    b+=2;
    //printf("計算了 %d 次\n",Cnt);
    }
    printf("計算了 %d 次\r\n",Cnt);
    printf("Pi=%d%d.\r\n", x[0],x[1]);
    for(i=0; i<DISPCNT; i++){
        if(i && ((i%100)==0))
        printf("\r\n");
        printf("%d",(int)x[i+2]);
    }
}