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Examples of rounding and truncating floating point values in C Plus Plus
C++ (C Plus Plus) provides built-in functions for truncating and rounding floating point data items. The ceil function calculates the next highest integer value for a given floating point value. The floor function calculates the next lowest integer value for a given floating point number.
ceil(x) returns the smallest integer not less than x.
floor(x) returns the largest integer not greater than x.
if x is a whole number, then ceil(x) and floor(x) both return x.
For example...
ceil(1.1) returns the integer 2.
floor(1.1) returns the integer 1.
The example code, below, is targeted for Microsoft C++ in Microsoft Visual Studio.
Examples of rounding and truncating floating point values in C Plus Plus
//****************************************************************************************
// ceil and floor.cpp *
// Examples of rounding and truncating floating point values in C++ *
// Author: nicomp *
// *
//****************************************************************************************
#include <iostream>
#include <math.h>
using namespace std;
void main()
{
double rounded = 0;
double num = .5;
cout << "\n ceil(" << num << ") " << ceil(num);
cout << "\n floor(" << num << ") " << floor(num);
if (num - floor(num) >= .5) rounded = floor(num + 1); else rounded = floor(num);
cout << "\n " << num << " rounds to " << rounded;
num = .4999;
cout << "\n ceil(" << num << ") " << ceil(num);
cout << "\n floor(" << num << ") " << floor(num);
if (num - floor(num) >= .5) rounded = floor(num + 1); else rounded = floor(num);
cout << "\n " << num << " rounds to " << rounded;
num = .50001;
cout << "\n ceil(" << num << ") " << ceil(num);
cout << "\n floor(" << num << ") " << floor(num);
if (num - floor(num) >= .5) rounded = floor(num + 1); else rounded = floor(num);
cout << "\n " << num << " rounds to " << rounded;
num = .51;
cout << "\n ceil(" << num << ") " << ceil(num);
cout << "\n floor(" << num << ") " << floor(num);
if (num - floor(num) >= .5) rounded = floor(num + 1); else rounded = floor(num);
cout << "\n " << num << " rounds to " << rounded;
num = .99;
cout << "\n ceil(" << num << ") " << ceil(num);
cout << "\n floor(" << num << ") " << floor(num);
if (num - floor(num) >= .5) rounded = floor(num + 1); else rounded = floor(num);
cout << "\n " << num << " rounds to " << rounded << "\n";
}
Examples of rounding and truncating floating point values in C Plus Plus
