Is (a - b) mod m same as ((a mod m) - (b mod m)) mod m?I’m having hard time dealing with it.Also if (a mod m) < (b mod m) then answer should be ((a mod m) - (b mod m) + m) mod m? I tried using library function fmodl but it also giving negative answers.Also if I use unsigned numbers then output is something different.
So what is the correct way to calculate (a-b) mod m where a>=b>=m in C++.
Assume the expression as ((a)mod m+(-b)mod m)mod m [expression (1)]
Now,define mod by yourself as
int mod(int a,int m)
{
return (a%m+m)%m;
}
The expression(1) can be represented in c++ as:
int ans=mod(mod(a,m)+(mod(-b,m),m);
Reference for my answer: [click here][1]
I gave the c++ implementation of the concept on the above link.
I hope this helps.
[1]: math - Modulo of a negative number - Stack Overflow