factorial function double fac (int num1), int resualt1=1; Data type is wrong, the result error is a bit, for reference:

 # include & lt; Iostream> 
#include $$
using namespace std; 

Double fac (int num1) {
Double resualt1=1.0; 
//int resualt1=1; 13!=6227020800 int 32 bits, the maximum value is: 2147483647 
While (num1 & gt; 
=1){
Resualt1 *=num1; 
Num1 -; 
} 
Return resualt1; 
} 

Double power (int num2, int num3) {
Int resualt2=1; 

While (num3 & gt; 
=1){
Resualt2 *=num2; 
Num3 -; 
} 
Return resualt2; 
} 

Double sin1 (double x) {
Double SQR=x * x; 
Double e=x; 
Double r=0; 
int i=1; 
Double f; 

While (I & lt; 13)={
F=e/fac (I); 

R=(I % 4==1)? R + f: r - f; 

E=e * SQR. 

I +=2; 
} 
return r; 
} 

Int main () {
Cout & lt; & lt; Sin1 (5) & lt; & lt; Endl; 
system("pause"); 
return 0; 
} 

//0.937584 
//please press any key to continue... 

Tried, no problem, thank you for your bosses