大整数乘法。。。。。

#include <stdio.h> #include <string.h> #include <stdlib.h> #include <memory.h> #define MAX 10001 int bigchenfa(int *sum,int *a,int *b,int lsum,int la,int lb) { int i,j,k ; memset(sum,0,sizeof(sum)); lsum = 0 ; for(i=1 ; i<= la ; i++) /*用数组模拟运算*/ for(j=1,lsum=i-1; j<= lb ; j++) {sum[++lsum] += b[j] * a[i] ;printf("sum[%d] = %d/n",lsum,sum[lsum]);} for(i=1 ; i<= lsum ; i++)/*进位处理*/ if (sum[i] >= 10) { if ( sum[lsum] >= 10) lsum ++ ; sum[i+1] += sum[i] / 10 ; sum[i] %= 10 ; } return lsum ; } int main(void) { int a[MAX]={0},b[MAX]={0},sum[MAX*2]={0} ; int la=0,lb=0,lsum=0; int i,j ; char sa[MAX],sb[MAX] ; scanf("%s %s",sa,sb); la = strlen(sa); lb = strlen(sb); for(i=1,j=la-1; i<= la ; i++,j--) {a[i] = sa[j] - '0' ; printf("a[%d] = %d",i,a[i]);}for(i=1,j=lb-1; i<= lb ; i++,j--) b[i] = sb[j] - '0' ; lsum = bigchenfa(sum,a,b,lsum,la,lb);for(i=lsum;i>= 1;i--)printf("%d",sum[i]); printf("/n"); system("pause"); return 0 ; }