If statements C++

deceit

I'm just trying to figure out how to get c++ to determine the smallest and largest of three numbers using if statements. Anyone any ideas how would be done.

JC 2K3

Can you show an attempt?

NeverSayDie

deceit wrote: »

I'm just trying to figure out how to get c++ to determine the smallest and largest of three numbers using if statements. Anyone any ideas how would be done.

Well, if you think about how you'd do this in your head, it'll help with the solution. For instance, I give you a list of numbers (a couple dozen, say), and ask you what the biggest one is. You'd look down through the list; "1, 10, 8, 15...". So far, it's 15 - you'll have that in your head as the biggest one, and keep going down the list. If you find a bigger one than 15, you'll swap that in your mind as the biggest one, and so on until the end of the list. Whatever you've got in your head as the biggest one when you reach the end, is the answer.

You just need to think about the above description in terms of loops, a variable or two and conditional (if) statements. Finding the smallest number is the same thing, and can be added to the above - if I asked you the smallest number in the list, you could do it at the same time, as long as you keep two numbers in your head.

JC 2K3

If it's just 3 numbers, and they're not in a list/array, i.e. the function is 'int get_max (int x, int y, int z)', then you don't need a loop, just 2 if statements.

That said, it's better to know how to do it generally for a long list of ints in a list/array.

deceit

Sorry I forgot to put up my attempt. Here it is, just keeps showing an error.

#include <iostream>
using namespace std;

int main()
{
	int num1, num2, num3;

	cout << "Enter Three numbers: " << endl;
	cin >> num1 >> num2 >> num3;

	if(num1 < num2)
		if(num1 < num3)
			cout << num1 << " is the smallest number." << endl;

	if(num2 < num1)
		if(num2 < num3)
			cout << num2 << " is the smallest number." << endl;

	if(num3 < num1)
		if(num1 < num2)
			cout << num2 << " is the smallest number." << endl

	system("pause");
	return 0;
}

deceit

Just read the error that was showing and realised was me just being stupid. It just missed a semi colon, must have read the error wrong last time :o

toiletduck

deceit wrote: »

Sorry I forgot to put up my attempt. Here it is, just keeps showing an error.

#include <iostream>
using namespace std;

int main()
{
	int num1, num2, num3;

	cout << "Enter Three numbers: " << endl;
	cin >> num1 >> num2 >> num3;

	if(num1 < num2)
		if(num1 < num3)
			cout << num1 << " is the smallest number." << endl;

	if(num2 < num1)
		if(num2 < num3)
			cout << num2 << " is the smallest number." << endl;

	if(num3 < num1)
		if(num1 < num2)
			cout << num2 << " is the smallest number." << endl

	system("pause");
	return 0;
}

Well the semi-colon error should have been immediately obvious. What tools are you using (visual studio?)?

And the code above won't give the third number as being the smallest ever.

I assume you're new to programming so I'll say always put brackets after your 'if' statements. Makes it easier to read and to add stuff to. Secondly why are you not using any 'else if/else' conditions in your code? It's better practice than a load of if statements on their own.

Six 'if's is a bit overkill for this. I'm sure someone has a shorter way but just off the top of my head you should be looking towards a solution like the following

if( (num1<num2) && (num1<num3))
	{
		cout << num1 << " is the smallest number\n";
	}

	else if ( (num2<num1) && (num2<num3))
	{
		cout << num2 << " is the smallest number\n";
	}

	else
		cout << num3 << " is the smallest number\n";

deceit

toiletduck wrote: »

Well the semi-colon error should have been immediately obvious. What tools are you using (visual studio?)?

And the code above won't give the third number as being the smallest ever.

I assume you're new to programming so I'll say always put brackets after your 'if' statements. Makes it easier to read and to add stuff to. Secondly why are you not using any 'else if/else' conditions in your code? It's better practice than a load of if statements on their own.

Six 'if's is a bit overkill for this. I'm sure someone has a shorter way but just off the top of my head you should be looking towards a solution like the following

if( (num1<num2) && (num1<num3))
	{
		cout << num1 << " is the smallest number\n";
	}

	else if ( (num2<num1) && (num2<num3))
	{
		cout << num2 << " is the smallest number\n";
	}

	else
		cout << num3 << " is the smallest number\n";

I am new to programming yes. I know it should have been obivious, just never noticed as back from work and havent slept yet. I'm using visual studio professional 2008 (get for free in work).Do you mean brackets like these after the if statements {}, I taught they where for when adding more than 1 bit of code. I havent learned about else and using && yet.

Anima

Well, some people prefer to always have them. I think it looks clearer so I always do it anyways. Up to you though.

toiletduck

deceit wrote: »

I am new to programming yes. I know it should have been obivious, just never noticed as back from work and havent slept yet. I'm using visual studio professional 2008 (get for free in work).

Good tool to have. Spotting errors and knowing what error ,messages actually mean is pretty important in learning programming!

Do you mean brackets like these after the if statements {}, I taught they where for when adding more than 1 bit of code.

Well they are, but some people (like myself) always use them even for single line expressions.

I havent learned about else and using && yet.

Ok, you learning by yourself or doing a course...? 'else' is the counterpoint to 'if' basically. And "&&" translates to 'AND'.

So

if( (num1<num2) && (num1<num3))

means if num1 is less than num2 and num1 less than three do something. It's called a logical operator, there are others (OR, XOR etc.).

The 'else' at the end of the code I slapped togther above means that if the first two 'ifs' aren't satisfied then whatever is contained within the 'else' is executed.

toiletduck

If you're just using 'if's' then your attempt will do fine, with minor changes (in bold) in the last two if statements.

#include <iostream>
using namespace std;

int main()
{
	int num1, num2, num3;

	cout << "Enter Three numbers: " << endl;
	cin >> num1 >> num2 >> num3;

	if(num1 < num2)
		if(num1 < num3)
			cout << num1 << " is the smallest number." << endl;

	if(num2 < num1)
		if(num2 < num3)
			cout << num2 << " is the smallest number." << endl;

	if(num3 < num1)
		if([B]num3[/B] < num2)
			cout << [B]num3[/B] << " is the smallest number." << endl

	system("pause");
	return 0;
}

DonkeyStyle \o/

highest and lowest at the same time...

// given num1, num2, num3
int largest = num3;
int smallest = num3;
if(num1 > largest) largest = num1;
else smallest = num1;
if(num2 > largest) largest = num2; 
else if(num2 < smallest) smallest = num2;

... works in Java anyhoo!

Chi chi

Are you restricted to using ONLY "if" for the flow control? It doesn't have to be that complicated....

deceit

Yes I was restricted as it was a question put forward to me and stated could only use a limited set of code.