Thank u for ur all warnings ! So ... for question 1 : i have used "if" ... actually i know that its better to use if , but i dont exactly know what i shoud do ... !!!! the following is my solution (incomplete solution!!):

Code:

#include <iostream>
#include <conio.h>
using namespace std;
int main(){
float a,b,c;
cout << "Enter 3 Numbers:" << endl;
cin >> a >> b >> c;
if (a+b<=c)
cout << "WoW! It can not be a Triangle" << endl;
if (a+c<=b)
cout << "WoW! It can not be a Triangle" << endl;
if (b+c<=a)
cout << "0WoW! It can not be a Triangle" << endl;
if (a==b==c)
cout << "Type of Triangle is equalateral triangle" << endl;
if (a*a==b*b+c*c)
cout << "Type of Triangle is right triangle" << endl;
if (b*b==a*a+c*c)
cout << "Type of Triangle is right triangle" << endl;
if (c*c==a*a+b*b)
cout << "Type of Triangle is right triangle" << endl;
if (a==b)
cout << "Type of Triangle is Isosceles Triangle" << endl;
if (a==c)
cout << "Type of Triangle is Isosceles Triangle" << endl;
if (b==c)
cout << "Type of Triangle is Isosceles Triangle" << endl;
getch();
return 0;
}

in this code i want check 3 conditions (if) and after print 1 message (to specify the type of triangle ) ... !! i think its better that i write my code compact !! , dont it ?... do u know what i mean ?!!!

and next ,when i enter 3 equal numbers , it prints "The type of triangle is Isosceles Triangle" 3 times and also it doesnt print equlateral triangle !!!! why ?!!

and for question 2 :

would u plz give me an idea to start ?!!!!!!!