Question

Can someone help with this assignment for C++? We were just introduced to loops, specifically while loop, do-while loop, for loop, and nested loops.
Write a program that reads a sequence of integers and prints the following:
The number of odd and even numbers of inputs
Use a sentinel value to signal the end of inputs. If the sentinel value is the first you enter, give a message "NO input is entered!".
Input Validation: Do not accept a negative number.

Answer 1

Answer:

1. #include <iostream>
3. using namespace std;
5. int main()
6. {
7.    int value;
8.    int oddCount = 0;
9.    int evenCount = 0;
10.    
11.    cout<<"Input a positive number: ";
12.    cin>> value;
13.    
14.    if(value == -1){
15.        cout<<"NO input is entered!";
16.        return 0;
17.    }
18.    
19.    if(value < -1) {
20.          cout<<"The input number must be positive";
21.          return 0;
22.    }
23.    
24.    while(value != -1){
25.        
26.        if(value % 2 == 0){
27.            evenCount++;
28.        }else{
29.            oddCount++;
30.        }
31.        cout<<"Input a positive number: ";
32.        cin>>value;
33.        if(value < -1){
34.              cout<<"Wrong input number\n";
35.              return 0;
36.        }
38.    }
39.    
40.    cout<<"Number of odd number: "<< oddCount<<"\n";
41.    cout<<"Number of even number: "<< evenCount;
42.  
43.    return 0;
44. }

Explanation:

Firstly, create three variables, value, oddCount and evenCount (Line 7-9). The value variable is to hold the input number from user (Line 11 -12). oddCount and evenCount are to track the number of occurrence of even and odd number of the user input (Line 21-25).

The sentinel value here is -1 and therefore if user enter -1 as first input, the message "NO input is entered!" will be displayed. (Line 14).

If user input a negative value other than -1 , display the alert message to user and terminate the program (Line 19-22).

We check if the value modulus by two is zero, this means it is an even number and then increment evenCount by one (Line 26-27). Otherwise increment oddCount by one (Line 28-29).  

After that prompt the user to input another number again and repeat the loop (Line 31-36). So long as the user don't enter -1, the while loop will just keep running.

At last, print the number of odd and even number (Line 40-41).