Fibonacci Number

#include <stdio.h>
#include <string.h>

char fibo[502][101];

void build_fibo_string()
{
    int i, j;
    for(i = 0; i < 502; i++){
        for(j = 0; j < 100; j++){
            fibo[i][j] = '0';
        }
        fibo[i][100] = '\0';
    }
}

void create_fibo_number(int n)
{
    int sum = 0, carry = 0;
    int i;
    for(i = 99; i >= 0; i--){
        sum = fibo[n-1][i] + fibo[n-2][i] + carry - '0' - '0';
        carry = (sum) / 10;
        fibo[n][i] = (sum) % 10 + '0';
    }
}

void build_fibo_number()
{
    int i, j;
    fibo[0][99] = '1';
    fibo[1][99] = '1';
    for(i = 2; i < 502; i++){
        create_fibo_number(i);
        if(fibo[i][0] > '0') break;
    }
}

int main()
{
    char s1[105], s2[105];
    char str1[105], str2[105];
    int count, i, j;

    build_fibo_string();
    build_fibo_number();

    while(1){
        scanf("%s %s", s1, s2);

        if(s1[0] == '0' && s2[0] == '0') break;

        int len1 = strlen(s1);
        int len2 = strlen(s2);
        int i, j;

        for(i = 0; i < 100 - len1; i++){
            str1[i] = '0';
        }
        for(i = 100 - len1, j = 0; i < 100; i++, j++){
            str1[i] = s1[j];
        }
        str1[i] = '\0';
        for(i = 0; i < 100 - len2; i++){
            str2[i] = '0';
        }
        for(i = 100 - len2, j = 0; i < 100; i++, j++){
            str2[i] = s2[j];
        }
        str2[i] = '\0';

        count = 0;
        for(i = 1; i < 476; i++){
            if(strcmp(str1, fibo[i]) <= 0 && strcmp(fibo[i], str2) <= 0) count++;
            else if(strcmp(fibo[i], str2) > 0) break;
        }
        printf("%d\n", count);
    }


    return 0;
}