ETH_Informatik/Informatik_I/Exercise_12/Task_2a

• Task Description
  • Input
  • Output
• Solution

Task Description

Complete the definition of function num_elements by editing the file num_elements.cpp according to its specified pre- and post conditions.

We provide a test program using the implemented function to find the number of elements in a specified interval of a vector.

Input

The test program accepts

• a vector length,
• the start index a, and
• the end index b.

For example

10 3 10

means a 10-element vector and the interval between index 3 and 9.

Output

The test program prints the number of elements in the interval [a,b).

For example the input given above, this value is 7.

Solution

#include "num_elements.h"
#include <iostream>

// PRE: a <= b are valid pointers to elements of the same contiguous memory
// block. POST: Returns the number of elements in between those pointers
// (starting at a, not including b).
int num_elements(const int *a, const int *b) { return b - a; }

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Made by JirR02 in Switzerland 🇨🇭