Sum of digits

[BrookeP]

My assignment is to have the user input an integer, output each digit and then add the sum of the digits. I've outputted the digits, but now I need to know how to get the sum. My digits are char variables and I know I need too change them to int. Thanks

  #include <iostream>

using namespace std;

int main(int argc, char** argv) {
	
	char num;
	
	
	cout << "Please enter an integer. ";
		while (cin)
	{
		
		cin >> num;
		cout << num << " ";
	}
	
	
	
	
	return 0;
}

[tath]

there are many ways to do it. Simplest one is looking up on the ascii table and transforming each char in to int.

int sum=0;
for(int=0;i<numberOfDigits;i++)
{
int number;

switch(num)
{
case '0':
number=0;
break;
[...]
case '9':
number=9;
break;
default:
//throw error
}
//if not error
sum += number;
}

[unstoppy]

Is that what you are looking for?

#include <iostream>

using std::cout;
using std::cin;
using std::endl;

int main()
{
	int num;
	int sum = 0;

	while(cin){
		cout << "Please enter the number:";
		cin >> num;
		sum += num;
		cout << "current sum is " << sum << endl;

	}
	

}

[BrookeP]

I need it to output each digit as well as the sum. I can't seem to remember how to do both.

[long double main]

You can use num - '0' to convert a digit to an integer.

That should work as long as your computer doesn't use some really bizarre character encoding system or something.

[BrookeP]

What about this? It isn't compiling correctly, any suggestions?

#include <iostream>

using namespace std;

int main(int argc, char** argv) {
	
	int maxSize = 25;
	int numbers[maxSize];
	int sum = 0;
	int num;
	cout << "Please enter an integer. ";
	for (int i = 0; i < maxSize; i++)
		{
			cin >> numbers[num];
		}
	
	for (int i = 0; i < maxSize; i++)
		{
			cout << numbers[num] << " ";
			sum += num;
		}
	
	
	cout << "Sum = " << sum;
		
return 0;
}
	

[long double main]

maxSize needs to be declared as const int maxSize = 25;.

On lines 14 and 19, I think you mean numbers[i] instead of numbers[num] (num is never initialized in your code, anyways).
Line 20 should probably also be numbers[i].

Other than that, what your program does is get 25 integers from the user and sum them up. If you were trying to compute the sum of the digits of a number, that's not what this program does (unless you enter one 25-digit number with each digit separated by a space).

Now, if you were planning on having each digit separated by a space, you would need some way to know when the number stops (otherwise you would always have to enter 25 digits).
Perhaps you could implement something where you stop reading input (and summing numbers) when you encounter a -1.

If you just want a sum, you don't even need an array -- just change numbers[num] to just num and combine your two for loops into one. (A for loop might not be appropriate here -- maybe a while loop that goes until you see a -1 or something would be better)

[BrookeP]

Thank you, how can I get the sum of the digits? I'm trying to test different ways to do it, but my compiler is freezing up.

[long double main]

I think your first post was the closest so far.

You just need that, my other post above (http://www.cplusplus.com/forum/beginner/121338/#msg660490 ), and a sum variable and you should be able to do it.

And wait...your compiler is freezing up? I've never heard of that happening before...

[unstoppy]

why dont you use vector instead of an array? it's a dynamic array you don't need to know the size of it before.

#include <iostream>
#include <vector>

int main()
{
	std::vector<int> container;
	int number;
	int sum = 0;
	while(true){
		std::cout << "Please enter a number" << std::endl;
		std::cin >> number;
		container.push_back(number);
		sum += number;
		std::cout << "The sum of [";

		//print all except the last int to get the commas right		
		for(int i=0; i<container.size()-1; i++){
			std::cout << container[i] << ", ";
		}
		
		//print the last int
		std::cout << container[container.size()-1] << "] is " << sum << std::endl;
	}

}

[Yanson]

#include <iostream>
#include <string>
using namespace std;

int main()
{
	
	string num = "";
	int total = 0;

	cout << "Please enter a number: ";
	getline(cin, num);

	for (int i = 0; i < num.size(); i++)
	{
		cout << num.at(i) << ' ';
		total += num.at(i) - '0';
	}

	cout << "\nThe total is: " << total << endl;

	cin.ignore();
	return 0;
}

or

include <iostream>
using namespace std;

int main()
{
	int total = 0;
	char temp = '0';


	cout << "Please enter a number: ";
	while ((temp = cin.get()) != '\n')
	{
		cout << temp << ' ';
		total += temp - '0';
	}

	cout << endl;
	cout << "The total is: " << total << endl;

	cin.ignore();
	return 0;
}