The setprecision() method of iomanip library in C++ is used to set the ios library floating point precision based on the precision specified as the parameter to this method.
Syntax:
setprecision(int n)
Parameters: This method accepts n as a parameter which is the integer argument corresponding to which the floating-point precision is to be set.
Return Value: This method does not return anything. It only acts as stream manipulators.
Example 1:
C++
// C++ code to demonstrate // the working of setprecision() function #include <iomanip> #include <ios> #include <iostream> using namespace std;
int main()
{ // Initializing the decimal
double num = 3.142857142857;
cout << "Before setting the precision: \n"
<< num << endl;
// Using setprecision()
cout << "Setting the precision using"
<< " setprecision to 5: \n"
<< setprecision(5);
cout << num << endl;
// Using setprecision()
cout << "Setting the precision using"
<< " setprecision to 9 : \n "
<< setprecision(9);
cout << num << endl;
return 0;
} |
Output:
Before setting the precision: 3.14286 Setting the precision using setprecision to 5: 3.1429 Setting the precision using setprecision to 9: 3.14285714
Example 2:
C++
// C++ code to demonstrate // the working of setprecision() function #include <iomanip> #include <ios> #include <iostream> using namespace std;
int main()
{ // Initializing the decimal
double num = 3.14;
cout << fixed;
cout << "Before setting the precision: \n"
<< num << endl;
// Using setprecision()
cout << "Setting the precision using"
<< " setprecision to 5: \n"
<< setprecision(5);
cout << num << endl;
// Using setprecision()
cout << "Setting the precision using"
<< " setprecision to 9: \n"
<< setprecision(9);
cout << num << endl;
return 0;
} |
Output:
Before setting the precision: 3.140000 Setting the precision using setprecision to 5: 3.14000 Setting the precision using setprecision to 9: 3.140000000
Reference: http://www.cplusplus.com/reference/iomanip/setprecision/