費氏數列

fibonacci_sequence.cpp

#include <iostream>
using namespace std;

int main()
{
    int numA = 1, numB = 1;
    cout << numA << ", " << numB << ", ";
    
    int oldNumA, oldNumB;
    
    while (numA + numB < 100) {
        cout << numA + numB << ", ";
        
        // 先把改變前的數字存起來
        oldNumA = numA;
        oldNumB = numB;
        
        numB = oldNumA + oldNumB;  // 新的Ｂ是舊的Ａ加上舊的Ｂ
        numA = oldNumB;            // 新的Ａ是舊的Ｂ
    }    
    
    return 0;
}

fibonacci_sequence_advanced.cpp

#include <iostream>
using namespace std;

int main()
{
    int numA = 1, numB = 1;
    cout << numA << ", " << numB << ", ";
    
    while (numA + numB < 100) {
        cout << numA + numB << ", ";
        
        numB = numA + numB;  // 新的Ｂ是「舊的Ａ加上舊的Ｂ」
        numA = numB - numA;  // 新的Ａ是「舊的Ｂ」，舊的Ｂ是「新的Ｂ減掉舊的Ａ」
    }    
    
    return 0;
}