Large number plus subtraction-Java implementation

The various types of data processed by the computer have a range that cannot be handled beyond the scope.

If you do a large number of operations subtraction, the ordinary method is certainly not, then we encounter large number of operations how to deal with it? Today introduces a method of large number subtraction operation

Ideas:

1. Use a character array as the storage medium for two extra-large integers.

2. A bitwise calculation of the traverse result is ten in one.

3. Flip the array that stores the results.

The following code:

1  Public classLargeintsub {2      Public Static voidMain (string[] args) {3         4String a= "6789";5String b= "123";6         int[]pa=stringtoints (a);7         int[]pb=stringtoints (b);8String result_sub=Sub (PA,PB);9SYSTEM.OUT.PRINTLN ("Sub result is:" +result_sub);Ten     } One      A      Public Static int[] stringtoints (String s) { -         int[] n =New int[S.length ()]; -          for(inti = 0;i<s.length (); i++){ theN[i] = Integer.parseint (s.substring (i,i+1)); -         } -         returnN; -     } +      -      Public StaticString Sub (int[]a,int[]b] { +StringBuffer sb=NewStringBuffer (); A         Booleanflag=false; at         if(a.length<b.length) { -             intc[]=A; -a=b;b=C; -flag=true; -         } -         inta_len= a.length-1; in         intB_len=b.length-1; -         intDegrade=0; to          while(a_len>=0| | B_len>=0){ +             intTemp=0; -             if(a_len>=0&&b_len>=0){ the                 if((A[a_len]-degrade) <B[b_len]) { *temp=a[a_len]+10-b[b_len]-degrade; $Degrade=1;Panax Notoginseng}Else{ -temp=a[a_len]-b[b_len]-degrade; the                 } +}Else if(a_len>=0){ Atemp=a[a_len]-degrade; theDegrade=0; +             } -Sb.append (temp+ ""); $              $a_len--;b_len--; -         } -         if(flag) { the             returnGetnum (Sb.append ("-"). reverse ()); -         }Wuyi         returnGetnum (Sb.reverse ()); the     } -      Public StaticString getnum (StringBuffer sb) { Wu          while(Sb.length () > 1 && sb.charat (0) = = ' 0 ') { -Sb.deletecharat (0); About         } $         returnsb.tostring (); -     } -  -}

Large number plus subtraction-Java implementation