算法--大数相加问题

#include<stdio.h>

void BigNumAdd(char* A, char* B, char* R, int n)
{
R[n+1]=0;
int n1=0, n2=0, sum=0, carry=0;
for(int  i=n-1; i>=0; i--)
{
n1=int(A[i]-'0');
n2=int(B[i]-'0');
sum=n1+n2+carry;
if(sum<=9)
{
carry=0;
R[i+1]=sum+'0';
}
else
{
carry=sum/10;
R[i+1]=sum%10+'0';
}
}
R[0]=carry+'0';
}

int main(int argc, char** argv)
{
char A[21]="25654194285418412198";
char B[21]="12428113942584564598";
char C[22];
BigNumAdd(A, B, C, 20);
return 0;
}