[UVa] 10862 - Connect the Cable Wires

I found a nice way to treat C Structures as same (almost) as C++ Classes, having functions for their operations. While solving this problem I implemented that.

Method:
Analyze the problem with cases 1, 2, 3, 4 and if needed, 5. You'll soon find out that it's about even positioned Fibonacci numbers.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char res[1000000];
typedef struct bNum
{
    int size;
    char val[2000];
} BigNum;

void setNum(char *val, BigNum *pThis)
{
    strcpy(pThis->val,val);
    pThis->size=strlen(val);
}
char *getNum(BigNum *pThis)
{
    return pThis->val;
}
int addNum(BigNum *p1, BigNum *p2, BigNum *p3)
{
    int i, j, k, car=0, cur;

    for (i=p1->size-1, j=p2->size-1, k=0 ; i>=0 || j>=0 ; i--, j--, k++)
    {
        cur = (i>=0?p1->val[i]:'0') + (j>=0?p2->val[j]:'0') + car - 96;
        if (cur>9)
        {
            car=1;
            res[k]=(cur-10)+'0';
        } else
        {
            car=0;
            res[k]=cur+'0';
        }
    }
    if (car)
    {
        res[k++]='1';
    }
    p3->size=k;
    for (--k, i=0 ; k>=0 ; k--, i++)
    {
        p3->val[i]=res[k];
    }
    p3->val[i]='\0';
}

BigNum fibs[5000];

int main()
{
    int i, n;
    setNum("1",&fibs[1]);
    setNum("1",&fibs[2]);

    for (i=3 ; i<=4001 ; i++)
    {
        addNum(&fibs[i-1],&fibs[i-2],&fibs[i]);
    }

    while (scanf("%d",&n) && n)
    {
        printf("%s\n",getNum(&fibs[2*n]));
    }
    return 0;
}