Exercise 6

Added Exercise 6

Informatik_I/Exercise_6/Task_2/README.org

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+#+TITLE: Task 2: Number of Occurrences
+#+AUTHOR: JirR02
+
+* Task
+
+Write a program using a vector to perform the following:
+
+1. Read integer values from standard input and insert them in a vector until a negative integer is encountered;
+1. Read an extra non-negative integer n;
+1. Output the number of occurrences of n encountered during phase (1).
+
+Your solution *must* split the sub-tasks of the program (reading the vector, counting the occurrences, and maybe other sub-tasks) into separate functions. Those functions *must* use the proper reference parameters to access the vector.
+
+*Note:* we consider solutions as incorrect if they use library functions (or data structures) beyond the ones discussed in the lectures so far to perform the actual computation.
+
+* Input
+
+A sequence of of integer values containing a single negative integer, in penultimate position.
+
+Example:
+
+#+begin_src shell
+0 1 1 2 3 5 8 13 21 -1 1
+#+end_src
+
+* Output
+
+The number of occurrences of the last integer in the sequence before the negative integer.
+
+Example: for the input given above, the number of occurrences of 1 before -1 occurs is
+
+#+begin_src shell
+2
+#+end_src
+
+* Reminder - How to use vector
+
+To define a vector (for example of integer numbers), you can use the following constructor
+
+#+begin_src cpp
+std::vector<int> my vec = std::vector<int>(length, init_value);
+#+end_src
+
+You can insert element at the back of the vector with:
+
+#+begin_src cpp
+my_vec.push_back(number);
+#+end_src
+
+To access the elements of the vector you have to use the random access ([]) operator:
+
+#+begin_src cpp
+std::cout << "First element: " << my_vec[0];
+#+end_src
+
+* Solution
+
+#+begin_src cpp
+#include <iostream>
+#include <vector>
+
+void readvec(std::vector<int>& vec, int& num) {
+  vec.push_back(num);
+}
+
+int occvec(std::vector<int>& vec, int& num, int& count) {
+  for (unsigned long i = 0; i < vec.size(); ++i) {
+    if (vec[i] == num)
+      ++count;
+  }
+  return count;
+}
+
+int main() {
+
+  int i;
+  int con;
+  int count = 0;
+  std::vector<int> vec;
+
+  std::cin >> i;
+
+  while (i >= 0) {
+    readvec(vec, i);
+    std::cin >> i;
+  }
+
+  std::cin >> con;
+
+  occvec(vec, con, count);
+
+  std::cout << count;
+
+  return 0;
+}
+#+end_src
+
+-----
+
+Made by JirR02 in Switzerland 🇨🇭