What is the usage of the = operator here?

Question

Below is my solution for finding the number of trailing zeros in a factorial, it works, i'm posting it to give an idea of how the algorithm works which is the sum of quotients of n divided by 5 ^ i, where i>0.

#include <cmath>
long zeros(long n) {
    long sum = 0;
    for (int i = 1;; ++i) {
        int m = n / pow(5, i);
        if (m == 0)
            break;
        else sum += m;
    }
    return sum;
}

I saw this solution which confused me with its use of the = operator. What does =5 mean in this context?

long zeros(long n) {
    long result = 0;
    while(n)
        result += n/=5;
    return result;
}

Answer 1

The expression result += n/=5 is equivalent to first updating the value of n to n/5 and then updating the value of result to result + n where n is now n/5 .

// result += n/=5 is same as doing
n = n / 5;
result = result + n;

Here the /= is analogous to += in the sense that n/=5 is equivalent to n = n/5

Answer 2

将值或变量分配给变量，即 m = n 表示如果 n 为 15，则 m 将是 n 的值，即 15