"Linear scan + high precision" Large integer divided by small integer to find remainder, decimal division

divide large integers by small integers to find remainder

The large integer divided by the small integer, the method for finding the remainder of the
inline int div (int a[], int n, int m) {//m=7 For example
  int ys = 0;
  for (int i = 0; i<n; i++) {
   ys*=10, ys+=a[i]; 
   ys%=m;
  }
  return ys;
}

Verify

void Testdiv () {
  int b[5] = {7, 9, 8, 0, 1};
  Assert (Div (b, 5, 1) ==0);
  Assert (Div (b, 5, 2) ==1);
  Assert (Div (b, 5, 3) ==1);
  Assert (Div (b, 5, 7) ==1);
}

Large integer Decimal Division

{int as[], int e, int k} represent a decimal. E represents the first decimal place subscript. K denotes the last subscript (including decimals).

Many for loops. A typical linear scan.

#include <iostream> #include <stdio.h> #include <string.h> #define MAXN using namespace std; 
  char* XJ (char *buf) {return buf;} void divide (int a, int b) {int AS[MAXN], CS[MAXN];
  int d=a/b;
  memset (as, 0, sizeof (AS));
  
  memset (CS, 0, sizeof (CS));
  Loading a= "as int i=maxn-1, j=0; 
  while (a>0) {as[j++]=a%10; a/=10;
  } j--;
    for (; i>=0&&j>=0; i--, j--) {as[i]=as[j];
  as[j]=0;
  }//as/b = "cs, note CS.E = AS.E, there is an extra 0 in front of CS.
  int e1= I, E2;
  Long long int c=0, t;
    for (i=maxn-1; i>=0; i--) {c*=10;
    t = c+as[i];
    cs[i]=t/b;
    C=t%b;
  if (i<=e1+1&&c==0) break;
  } if (i<0) i=0;
  
  int k = i;  
  CS = "Buf char buf[maxn+2];
  for (i=maxn-1; i>e1+1; i--)//Skip Excess 0 if (cs[i]!=0) break;
  for (j=0; i>e1; I--, j + +) {//Record integer part buf[j]= ' 0 ' +cs[i];  } if (i>=k) buf[j++]= '. ';
  Whether there is a small number of parts e2=j; for (i=e1; i>=k && j<maxn+1; I--, j + +) {//Decimal part//cout<<i<< ":" <<cs[i]<<endl; 
  buf[j]= ' 0 ' +cs[i];

  } buf[j]=0;
  Print BUF cout<<d;
    if (e2<j) {cout<< ".";
  cout<< (BUF+E2);
} cout<<endl;
  } int main () {int a=2, b=3;
  cout<< "input a B" <<endl;
    while (~SCANF ("%d%d", &a, &b)) {cout<<a<< "/" <<b<< ":" <<endl;
  Divide (A, b);
} return 0;
 }