Mixing
How to get even & odd numbers correctly from a positive integer in c++?
How to get even & odd numbers correctly from a positive integer in c++?
I am new to C++... I am having trouble to get even & odd numbers from a positive integer.. But for some reason it is not displaying it correctly. So, in my if-else statement I am using the mod operator and using even = even * 10 + remainder; for even numbers and for the odd number I am trying to do is: odd = odd * 10 + remainder;.. I am getting an error with
mod
even = even * 10 + remainder;
odd = odd * 10 + remainder;
Invalid operands to binary expression.
So, can anyone help me solve the problem by getting the even & odd numbers from a positive integer. Thanks.
Here is my code:
#include <iostream>
#include <fstream> // for file stream.
using namespace std;
int main() {
// Variables
int x, reversedNumber, remainder;
// Creating String variables and setting them to empty string.
string even = "", odd = "";
// Creating a file.
ofstream out;
out.open("outDataFile.txt");
// creating a character variable
// for the user input if they want to use the program again.
char ch;
do {
// Even number.
even = "";
// Odd number.
odd = "";
// Reversed number
reversedNumber = 0;
// Prompt the user to enter a positive integer.
cout << "nEnter a positive integer and press <Enter> ";
// Validate user input.
// if (cin >> x && x < 0) {
//
// } else {
// cout << "Invalid entry, Try again." << endl;
// cin.clear();
// while (cin.get() != 'n');
// }
// Display Results to the screen
cout << "the original number is " << x << "n";
// Display results in the text file.
out << "the original number is " << x << "n";
// Display number reversed.
cout << "the number reversed ";
// Display number reversed in text file.
out << "the number reversed ";
//Reversing the integer.
while (x != 0) {
remainder = x % 10;
reversedNumber = reversedNumber * 10 + remainder;
// Display on screen
cout << remainder << " ";
// Display in text file.
out << remainder << " ";
x /= 10;
}
// Display the results on screen and in the text file.
cout << "n";
out << "n";
// Reading the reverse numbers result.
while (reversedNumber != 0) {
remainder = reversedNumber % 10;
// Checking if the number is even or odd.
if (remainder % 2 == 0) {
// even = even * 10 + remainder;
} else {
// odd = odd * 10 + remainder;
}
reversedNumber /= 10;
}
//Displaying the even numbers.
if (even != "") {
cout << "the even digits are " << even << "n";
out << "the even digits are " << even << "n";
}
// If it is not even then display..
else {
cout << "There are no even digits n";
out << "There are no even digits n";
}
//Display the odd results.
if (odd != "") {
cout << "the odd digits are " << odd << "n";
out << "the odd digits are " << odd << "n";
}
// If its not odd then display.
else {
cout << "There are no odd digits n";
out << "There are no odd digits n";
}
// just a divider to divide the results inside text file.
out << "----------------- n";
// Prompt the user if they want to use the program again.
cout << "nDo you like to continue/repeat? (Y/N):";
// get the input from user.
cin >> ch;
if ((ch == 'Y') || (ch == 'y')) {
} else {
cout << "nGoodbye!" << endl;
}
} while (ch == 'y' || ch == 'Y');
// close the text file.
out.close();
return 0;
}
+
Upon further inspection of your code, you are attempting to do
even * 10 + remainder; when even is std::string....what do you expect that expression to give you?– smac89
2 days ago
even * 10 + remainder;
even
std::string
I see that it is a string.... how can I accomplish this, prior of being new to c++, I need some help - so I can grasp some snippets from you guys .
– Harut Simonyan
2 days ago
Convert the string to a number before using it like that...See en.cppreference.com/w/cpp/string/basic_string/stol. Then after you are done, convert it back to a string with en.cppreference.com/w/cpp/string/basic_string/to_string
– smac89
2 days ago
is it the place when I am calling
even = "" and odd="" ?– Harut Simonyan
2 days ago
even = ""
odd=""
1 Answer
1
Convert the number to string before appending it to the string:
while (reversedNumber != 0) {
remainder = reversedNumber % 10;
// Checking if the number is even or odd.
if (remainder % 2 == 0) {
even += std::to_string(remainder);
} else {
odd += std::to_string(remainder);
}
reversedNumber /= 10;
}
If you are uncomfortable with using std::to_string, then you can have even and odd as integers and simply do this:
std::to_string
even
odd
int even = 0;
int odd = 0;
...
while (reversedNumber != 0) {
remainder = reversedNumber % 10;
// Checking if the number is even or odd.
if (remainder % 2 == 0) {
even *= 10 + remainder;
} else {
odd *= 10 + remainder;
}
reversedNumber /= 10;
}
in my declaration
string even = "", odd = ""; should I change it to int ?– Harut Simonyan
2 days ago
string even = "", odd = "";
int
@HarutSimonyan, yes. Change it to
int even = 0, odd = 0;– smac89
2 days ago
int even = 0, odd = 0;
and set it equal to 0 , right?
– Harut Simonyan
2 days ago
@HarutSimonyan, yes, I just edited my comment above
– smac89
2 days ago
@HarutSimonyan Everywhere you were doing
even = some_string, change it to even = 0. The same goes for odd– smac89
2 days ago
even = some_string
even = 0
odd
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There is no overload for the
+operator for string and integers. See here en.cppreference.com/w/cpp/string/basic_string/operator%2B– smac89
2 days ago