Why this is causing error ? How to resolve it

Question

#include <stdio.h>

int main() {
int a=10, b=3,max;
a>b ? max=a : max=b;
printf("%d\n",max);
return 0;
}

Answer 1

Line 3 should be like this:
Max = a > b ? a : b;

Answer 2

devanille by adding parenthesis what the reason so the code is executed correctly