Very Basic C++ help

[fdgod33]

My problem is whenever i run this syntax on c++, it counts -1 as part of the loop.
i did something similar to the "THENEWBOSTON" syntax, his -1 was not included

Basically, I'm looking for the average of ages..




#include <iostream>

using namespace std;

int main()
{
int age;
int numberofpeople = 0;
int sumofage= 0;

while (age !=-1){

cout << "Enter age value here or press -1 to quit" << endl;
cin >> age;

sumofage = sumofage + age;
numberofpeople ++;



}

cout << "The number of people is " << numberofpeople << endl;

cout << sumofage/numberofpeople;



return 0;
}


Whenver i compile this, it sees -1 as a value, how can i prevent this from happening

[december0123]

cout << "The number of people is " << numberofpeople -1 << endl;

cout << (sumofage + 1)/(numberofpeople - 1);The simplest solution is usually the best one :)

[trent.josephsen]

I think rewriting the loop as a do...while is probably a simpler solution:


int age = 0;
int numberofpeople = -1;
int sumofage = 0;

do {
numberofpeople++;
sumofage = sumofage + age;
cout << "Enter age value here or press -1 to quit" << endl;
cin >> age;
} while (age != -1);
Less magic.

@OP, you should wrap your code in [CODE] tags when posting, which will help us read your code more easily (provided you indented it well, of course).

[3Miro]

#include <iostream>

using namespace std;

int main()
{
int age = 0;
int numberofpeople = -1;
int sumofage= 0;

while (age !=-1){

sumofage = sumofage + age;
numberofpeople ++;

cout << "Enter age value here or press -1 to quit" << endl;
cin >> age;


}

cout << "The number of people is " << numberofpeople << endl;

cout << sumofage/numberofpeople;

return 0;
}

First of all, you should always initialize your variables. You were checking the value of (age!=-1) before any value was stored in it.

Second, you should count how many times the loop is counted, when -1 is entered, you still count both the age and number of people.

I hope I didn't just do your homework for you.

[dwhitney67]

I doubt the OP intended to add -1 to the sum-of-ages??? Yet some of the previous examples seems to show that or increment numberofpersons prematurely. :-k

The program should check the value of the variable 'age' before using it within an computation. Similarly, the value of numberofpersons should be checked before using it as a divisor. Something like:


#include <iostream>

int main()
{
using std::cout;
using std::cin;
using std::endl;

int sumofage = 0;
int numberofpeople = 0;

while (true)
{
int age = -1;

cout << "Enter age value, or -1 to quit: ";
cin >> age;

if (age == -1) break;

sumofage += age;
++numberofpeople;
}

cout << "\nNumber of people: " << numberofpeople << endl;

if (numberofpeople > 0)
{
cout << "Avegage age of people: " << (float) sumofage / numberofpeople << endl;
}
}


P.S. It is important to reset 'age' for each cycle around the loop; one never knows if the user will force an EOF (ctrl-d) when the cin is being used to read user input.