# Guess Number Higher or Lower in C++

C++Server Side ProgrammingProgramming

Suppose we are playing the Guess Game. The properties of this game is as follows −

Player 1 will pick a number from 1 to n. player2 have to guess which number I picked. Every time player2 guess wrong, player1 will tell player2 whether the number is higher or lower.

We can use the function guess(num) which will return 3 possible results as follows −

• -1 − Player1's number is lower

• 1 − Player1's number is higher

• 0 − Number is matched

So, if the input is like n = 10, pick = 5, then the output will be 5.

To solve this, we will follow these steps −

• l := 1,r := n

• while l −= r, do −

• m := l+(r - l)/2

• if guess(m) is the same as 0, then −

• return m

• if guess(m) is the same as -1, then −

• r := m - 1

• Otherwise

• l := m + 1

• return 0

## Example

Let us see the following implementation to get a better understanding −

Live Demo

#include <bits/stdc++.h>
using namespace std;
class Solution {
private:
int number;
int guess(int num){
if(number > num)
return 1;
if(number < num)
return -1;
return 0;
}
public:
Solution(int n){
number = n;
}
int guessNumber(int n) {
int l=1,r=n,m;
while(l<=r){
m=l+(r-l)/2;
if(guess(m)==0)
return m;
if(guess(m)==-1)
r=m-1;
else
l=m+1;
}
return 0;
}
};
main(){
Solution ob(5); //pick = 5
cout << (ob.guessNumber(10));
}

## Input

5,10

## Output

5