In this C++ tutorial, you will learn how to truncate the decimal part of given number using trunc() function of cmath, with syntax and examples.
C++ trunc()
C++ trunc() truncates the decimal part of given number (argument).
In terms of rounding, trunc() function rounds the number towards zero and returns the nearest integral value.
Syntax
The syntax of C++ trunc() is
trunc(x)
where
| Parameter | Description |
|---|---|
| x | A double, float, or long double value. |
Returns
The return value depends on the type of value passed for parameter x.
The return value of trunc(x) is
- double if x is double.
- float if x is float.
- long double if x is long double.
The synopsis of trunc() function is
double trunc(double x); float trunc(float x); long double trunc(long double x); double trunc(T x); // for integral type argument values
trunc() is a function of cmath library. Include cmath library in the program, if using trunc() function.
Example
In this example, we read a double value from user into x, and find its truncated value using trunc() function.
C++ Program
#include <iostream>
#include<cmath>
using namespace std;
int main() {
double x;
cout << "Enter a number : ";
cin >> x;
double result = trunc(x);
cout << "trunc(" << x << ") : " << result << endl;
} Output
Enter a number : 3.14 trunc(3.14) : 3 Program ended with exit code: 0
Enter a number : -3.14 trunc(-3.14) : -3 Program ended with exit code: 0
Enter a number : -0.21 trunc(-0.21) : -0 Program ended with exit code: 0
Conclusion
In this C++ Tutorial, we learned the syntax of C++ trunc(), and how to use this function to find the truncated value of given number, with the help of examples.