View Compilation Error

0_0_19954352_5339.cpp:9:1: error: '_int64' does not name a type
 _int64 fac(int m){
 ^
0_0_19954352_5339.cpp: In function 'int main()':
0_0_19954352_5339.cpp:26:29: error: 'fac' was not declared in this scope
   printf("%.2f\n",a[m]/fac(m));
                             ^