To find the HCF (Highest Common Factor) or GCD (Greatest Common Divisor) of two or more numbers, make prime factors of the numbers and choose the common prime factors. Then the take the highest common factor this highest common factor is HCF of number. For example;
Find HCF or GCD
Suppose find HCF of 4 and 8 4=4*1=2*2 8=8*1=2*4=2*2*2 Factor of 4 is 1, 2, 4 Factor of 8 is 1, 2, 4, 8 So, common factor of 4 and 8 is 1, 2, 4 and highest common factor is 4 hcf of 4 and 8 is: 4
C++ Program to Find GCD
#include<iostream.h> #include<conio.h> void gcd(int,int); void main() { int a,b; clrscr(); cout<<"Enter two numbers: "; cin>>a>>b; gcd(a,b); getch(); // return 0; } //function to calculate g.c.d void gcd(int a,int b) { int m,n; m=a; n=b; while(m!=n) { if(m>n) m=m-n; else n=n-m; } cout<<"\nH.C.F of"<<a<<" & "<<b<<" is "<<m; }
Output
Enter any two number: 3 15 H.C.F of 3 & 15 is 15