Order numbers in c++ and recognize the repeated ones - c++

Question

I was trying to make a program in c++ that should order 3 random numbers (the user will write them) and then print which is the higher and the lower, but if two numbers or more are equal should print it.
New code:
#include <iostream>
using namespace std;
int main()
{
int num1;
int num2;
int num3;
cout << "num1" << endl;
cin >> num1;
cout << "num2" << endl;
cin >> num2;
cout << "num3" << endl;
cin >> num3;
if(num1 == num2 && num3==num2 && num1==num3){
cout << "all numbers are equal";
}
else if (num1 == num2){
cout << "num1 and num2 are equal";
}
else if (num2 == num3){
cout << "num2 and num3 are equal";
}
else if(num3 == num1){
cout << "num1 and num3 are equal";
}
else{
if (num1 != num2 && num2 != num3 && num3 != num1){
if (num1 > num2 && num1 > num3){
cout << "higher is num1";
}
else if(num2 > num1 && num2 > num3){
cout << "higher is num2";
}
else if(num3 > num1 && num3 > num2){
cout << "higher is num3";
}
}
}
return 0;
}
New problem:
The programm needs to know which is the lowest too, so how can I do that?
Old code:
#include <iostream>
using namespace std;
int main()
{
int num1;
int num2;
int num3;
cout << "num1" << endl;
cin >> num1;
cout << "num2" << endl;
cin >> num2;
cout << "num3" << endl;
cin >> num3;
if(num1 == num2 && num3==num2 && num1==num3){
cout << "all your numbers are equal";
}
if (num1 != num2 && num2 != num3 && num3 != num1){
if (num1 > num2 && num1 > num3){
cout << "num1";
}
else if(num2 > num1 && num2 > num3){
cout << "num2";
}
else /*(num3 > num1 && num3 > num2)*/{//Here I tried to use and else if
cout << "num3";
}
}
return 0;
}
Old problem
This code is all wrong, but I don't know what I'm doing wrong, please help me.
And I have a last question, do I have a limit of if's into a if sentence? or I just can't write two else if or..? Thanks.

Answer 1

#include <iostream>
#include <set>
int main()
{
std::set<int> numbers;
int input;
for (int i=1; i<=3; ++i) {
std::cout << "Enter number " << i << ": ";
std::cin >> input;
numbers.insert(input);
}
if (numbers.size() < 3) {
std::cout << "You entered the same number more than once, silly!" << std::endl;
std::cout << "Nevertheless, ";
}
std::cout << "the maximum number is " << *numbers.rbegin() << std::endl;
}
The important feature of this code is that it takes advantage of the properties of std::set which are:
It keeps all its elements in sorted order
It does not allow duplicate elements
std::set::rbegin is used to get the last element, which is the largest number (because the numbers are automatically sorted).
This code does not display which numbers are the largest and smallest, but this can easily be added. For example, std::set::insert returns information that can allow you to determine which insertion failed in the set. An std::set can contain only single copies of its contained objects. Therefore, if the user enters a number more than once the calls to insert will fail.

Answer 2

The following piece of code solves your purpose. It has three functions findLargest, findSmallest and checkEqual. This is a very basic program and can be modified to your needs on how to display and what to return etc etc.
#include <iostream>
using namespace std;
void findLargest(int n1,int n2,int n3)
{
if(n1>n2 && n1>n3)
{
cout<<"Largest number is :"<<n1;
cout<<"\n";
}
else if((n2>n1) && (n2>n3))
{
cout<<"Largest number is :"<<n2;
cout<<"\n";
}
else
{
cout<<"Largest number is :"<<n3;
cout<<"\n";
}
}
void findSmallest(int n1,int n2,int n3)
{
if(n1<=n2 && n1<=n3)
{
cout<<"Smallest number is :"<<n1;
cout<<"\n";
}
else if((n2<=n1) && (n2<=n3))
{
cout<<"Smallest number is :"<<n2;
cout<<"\n";
}
else
{
cout<<"Smallest number is :"<<n3;
cout<<"\n";
}
}
int checkEqual(int n1,int n2,int n3)
{
if(n1==n2 && n2==n3 && n3==n1)
{
cout<<"All three are equal";
cout<<"\n";
}
else if(n1==n2||n2==n3||n3==n1)
{
cout<<"Two numbers are equal";
cout<<"\n";
}
else
{
cout<<"None are equal.. Finding Largest and Smallest....!!";
cout<<"\n";
}
}
int main() {
int num1,num2,num3;
cout<<"Enter the numbers";
cin>>num1>>num2>>num3;
cout<<"\n";
checkEqual(num1,num2,num3);
findSmallest(num1,num2,num3);
findLargest(num1,num2,num3);
return 0;
}
Ideone link: http://ideone.com/hz4keQ
Hope it helps. :)