Question

C++ CLion

using Namespace std

Draw a picture of the array that would be created by the following code

int data[10] = {1, 1};
for( int index = 2; index < 8; ++index )
data[ index ] = data[index – 1] + data[index – 2];

Answer 1

   int data[10] = {1, 1}; // will create an array of int data of size 10 where the first 2 elements i.e index 0 and 1 will have value 1 and other locations will have value of 0 (since by default integer variables are set to 0 in C++)

data[0] = 1

data[1] =1

data[2] ... data[9] = 0

   // loop that starts from 2 and continues till index 7 (inclusive)
   for(int index = 2; index < 8; ++index)
       data[index] = data[index-1] + data[index-2]; // sets data at index to sum of values of data at index-1 and index-2

The above loop iterations :

1st Iteration, index = 2,

data[2] = data[1] + data[0]

= 1 + 1 = 2

2nd Iteration , index = 3

data[3] = data[2] + data[1]

= 2 + 1 = 3

3rd Iteration , index = 4

data[4] = data[3] + data[2]

= 3 + 2 = 5

4th Iteration , index = 5

data[5] = data[4] + data[3]

= 5 + 3 = 8

5th Iteration , index = 6

data[6] = data[5] + data[4]

= 8 + 5 = 13

6th Iteration , index = 7

data[7] = data[6] + data[5]

= 13 + 8 =21

7th Iteration , index = 8

Since index = 8 , it exits the loop

After the loop, array:

array = {1,1,2,3,5,8,13,21,0,0}

After the execution of above code the array will look like:

1

1

2

3

5

8

13

21

0

0