Problem when setting precision with cout: Candidates are: ? precision() ? precision(?)

[puertas12]

I want to set a specific precision in a float number. So I found the public member function "std::ios_base::precision" and did a small exercise that worked correctly:

#include <iostream>
using namespace std;

int main() {
	double f=3.14159;
	cout.precision(10);
	cout.setf(ios::fixed, ios::floatfield);
	cout<<f<<endl; //cout displays 10 numbers after the comma
	return 0;
}

Now I want to use this feature in my exercise:

#include <iostream>
#include <chrono>
#include <thread>

using namespace std;

//Prototypes
void f();

int main() {
	clock_t c_start=clock();
	auto t_start=chrono::high_resolution_clock::now();
	thread t1(f);
	thread t2(f);
	t1.join();
	t2.join();
	clock_t c_end=clock();
	auto t_end=chrono::high_resolution_clock::now();

	//cout.unsetf(ios::floatfield);
	cout.precision(2);   //The compiler complains at this line
	cout.setf(ios::fixed, ios::floatfield);
	cout<<"CPU time used"<< 1000.0 * (c_end-c_start) / CLOCKS_PER_SEC << " ms\n";



	return 0;
}

void f(){
	volatile double d=0;
	for(int n=0;n<10000;n++){
		for(int m=0; m<10000; m++){
			d += d*n*m;
		}
	}
}

The compiler complains at

cout.precision(2);

with the following error:

Candidates are: ? precision() ? precision(?)

Does anybody know why I receive this error and how can I solve it?
Thanks.

[masecla33]

Everything you did is correct, and it compiled just fine to me, but i had to first set the flag of
-std=c++11, because one of your libraries requires so, Other than that, it compiled just fine for me, i don't know what issue you have there.

[puertas12]

I also set the flag "-std=c++11" but I still have the error. @masecla33 It is strange that for you is working. I wonder what it can be wrong with my compilation...

[jlb]

Perhaps you need to #include <iomanip> which contains the definitions of the io manipulator functions.

[masecla33]

Here is the exact code i have been using.

#include <iostream>
#include <chrono>
#include <thread>
#include <iomanip> //for me it compiled just fine without this tough i added just to be sure

using namespace std;

//Prototypes
void f();

int main() {
	clock_t c_start=clock();
	auto t_start=chrono::high_resolution_clock::now();
	thread t1(f);
	thread t2(f);
	t1.join();
	t2.join();
	clock_t c_end=clock();
	auto t_end=chrono::high_resolution_clock::now();

	//cout.unsetf(ios::floatfield);
	cout.precision(2);   //The compiler complains at this line
	cout.setf(ios::fixed, ios::floatfield);
	cout<<"CPU time used"<< 1000.0 * (c_end-c_start) / CLOCKS_PER_SEC << " ms\n";



	return 0;
}

void f(){
	volatile double d=0;
	for(int n=0;n<10000;n++){
		for(int m=0; m<10000; m++){
			d += d*n*m;
		}
	}
}

Try making another project with the same code and stuff.