To bosses guidance; using the following formula for cos (x) approximation, and accurate to the last-CodePudding

Topics are as follows:

The code below

 
# include & lt; Stdio. H> 
# include & lt; Math. H> 

Double funcos (double e, double x); 

Int main () 
{
Double e, x; 

Lf the scanf (" % % lf ", & amp; E, & amp; X); 
Printf (" cos (. % 2 f)=%. 6 f \ n ", x, funcos (e, x)); 

return 0; 
} 
Double funcos (double e, double x) 
{
Double t=1.0; 
Double l=1.0; 
Int I; 
Int j=2; 
Double the total; 
Double sum; 
While ((t/l) & gt; E)//when does not meet the precision cycle 
{
T=pow (x, j); 
For (I=1; I & lt;=j; I++) 
{
L *=I;//for molecular 
} 

Total +=- (t/l);//a single 

The sum +=total; 

J +=2;//increment index + 2 
} 
Return the sum + 1; 
}

I think that no problem, but the code is wrong, where I went wrong, don't see

CodePudding user response:

Your custom function, total and sum uninitialized,

In addition, the output of the double should use % lf, should be a % of the building Lord. 2 lf

CodePudding user response:

refer to the original poster mountains roll also thinks response:

title as follows:

The code below

 
# include & lt; Stdio. H> 
# include & lt; Math. H> 

Double funcos (double e, double x); 

Int main () 
{
Double e, x; 

Lf the scanf (" % % lf ", & amp; E, & amp; X); 
Printf (" cos (. % 2 f)=%. 6 f \ n ", x, funcos (e, x)); 

return 0; 
} 
Double funcos (double e, double x) 
{
Double t=1.0; 
Double l=1.0; 
Int I; 
Int j=2; 
Double the total; 
Double sum; 
While ((t/l) & gt; E)//when does not meet the precision cycle 
{
T=pow (x, j); 
For (I=1; I & lt;=j; I++) 
{
L *=I;//for molecular 
} 

Total +=- (t/l);//a single 

The sum +=total; 

J +=2;//increment index + 2 
} 
Return the sum + 1; 
}

I think that no problem, but the code is wrong, where I went wrong, don't see

This single comment of one line of what you mean?
You see your problem, plus or minus a didn't control well, how could the answer right?
Positive and negative items with *=1 (that is, by 1) control, so change to total=1.0 (initial value), the sum=0
Then a for loop in the
Total +=- (t/l); The sum +=total; To sum +=total * (t/l); Total *=1;//total as a flag of plus or minus sign, every operation change a symbol

CodePudding user response:

 double funcos (double e, double x) 
{
Double k=1.0; 
Double s; 
Double total=1; 
Int j; 
Double I=2; 
Int falg=1; 
Int sum=1; 

While (k & gt;=e) 
{
S=pow (x, I); 

For (j=1; J & lt;=I; J++) 
{
The sum *=j; 

} 
K=s/sum; 
Total=total + k * falg; 
Falg=- falg; 

I +=2; 
} 
Return the total; 
}

Changed or not

CodePudding user response:

Every time you check sum factorial right well, calculating factorial initialized again?
Or you could get rid in the for j=1, on the outside to initialize the j; Or before each for j loop initialization sum
In addition, while (k>=e) also has a problem, assuming that k=s/sum is less than e, the back of the totle=totle + k * flag or performed, which is going to calculate a,