Multiplication of large numbers

1 # Include <iostream> 2 # Include <stdio. h> 3 # Include <math. h> 4 # Include <algorithm> 5 # Include < String . H> 6 # Include < String > 7 # Include <ctime> 8 # Include <queue> 9 # Include <list>10   # Define INF 9999999 11   # Define Maxn 10000 12   Using   Namespace  STD;  13   //  Priority_queue <int, vector <int>, greater <int> PQ;  14   15   Int  Main ()  16  {  17       Int A [ 50 ], B [ 50 ], C [ 100  ];  18       String  Sa, Sb;  19       While (CIN> Sa> SB)  20   {  21          Int  I, J;  22           For (I = sa. Size ()- 1 , J = 0 ; I> = 0 ; I --, J ++ )  23 A [J] = sa [I]- '  0  '  ;  24           For (I = sb. Size ()-1 , J = 0 ; I> = 0 ; I --, J ++ )  25 B [J] = Sb [I]- '  0  '  ;  26 Memset (C, 0 , Sizeof  (C ));  27           For (I =0 ; I <SA. Size (); I ++ )  28               For (J = 0 ; J <sb. Size (); j ++ )  29 C [I + J] + = A [I] * B [J];  30           For (I = 0 ; I <SA. Size () + sb. Size () + 2 ; I ++ )  31  {  32 C [I + 1 ] + = C [I]/ 10  ;  33 C [I] % = 10  ;  34   }  35           Int Flag = 0  ;  36           For (I = sa. Size () + sb. Size () + 2 ; I> = 0 ; I -- )  37               If (Flag | C [I])  38   {  39 Cout < C [I];  40 Flag = 1  ;  41   } 42 Cout < Endl;  43   }  44       Return   0  ;  45 }