fix a typo (#424)

HKalbasi · jakobkogler · commit 899109e4405f · 2019-04-07T18:05:47.000+02:00
diff --git a/src/algebra/primality_tests.md b/src/algebra/primality_tests.md
@@ -17,7 +17,7 @@ If it is a divisor, than $n$ is definitely not prime, otherwise it is.
 ```cpp
 bool isPrime(int x) {
     for (int d = 2; d * d <= x; d++) {
-        if (x % d == 2)
+        if (x % d == 0)
             return false;
     }
     return true;

Original file line number	Diff line number	Diff line change
`@@ -17,7 +17,7 @@ If it is a divisor, than $n$ is definitely not prime, otherwise it is.`
`17`	`17`	```cpp
`18`	`18`	`bool isPrime(int x) {`
`19`	`19`	`for (int d = 2; d * d <= x; d++) {`
`20`		`- if (x % d == 2)`
	`20`	`+ if (x % d == 0)`
`21`	`21`	`return false;`
`22`	`22`	`}`
`23`	`23`	`return true;`