cin handles double and float type values
#include <iostream>
using namespace std;
int main()
{
int myInt;
long myLong;
double myDouble;
float myFloat;
unsigned int myUnsigned;
cout << "int: ";
cin >> myInt;
cout << "Long: ";
cin >> myLong;
cout << "Double: ";
cin >> myDouble;
cout << "Float: ";
cin >> myFloat;
cout << "Unsigned: ";
cin >> myUnsigned;
cout << "\n\nInt:\t" << myInt << endl;
cout << "Long:\t" << myLong << endl;
cout << "Double:\t" << myDouble << endl;
cout << "Float:\t" << myFloat << endl;
cout << "Unsigned:\t" << myUnsigned << endl;
return 0;
}constant floats, floating point variables
#include <iostream>
using namespace std;
int main(){
float rad;
const float PI = 3.14159F;
cout << "Enter radius of circle: ";
cin >> rad;
float area = PI * rad * rad;
cout << "Area is " << area << endl;
return 0;
}Define function whose parameter and return value are both float
#include <iostream>
using namespace std;
float cube_number(float num);
int main()
{
float number;
float number3;
cout << "Please enter a number \n";
cin >> number;
number3 = cube_number(number);
cout << number << " cubed is " << number3;
return 1;
}
float cube_number(float num)
{
float answer;
answer = num * num * num;
return answer;
}Please enter a number
123
123 cubed is 1.86087e+006"
Display decimal and float with format
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
cout << 2002 <<endl;
cout << "In hex " << hex<< 2002 <<endl;
cout.setf(ios::scientific,ios::floatfield);
cout <<987.123456 <<endl;
cout << setprecision(3) << 987.123456 <<endl;
cout.fill("X");
cout.width(10);
cout << 1234 <<endl;
cout.setf(ios::left,ios::adjustfield);
cout.width(10);
cout << 1234 <<endl;
return 0;
}float number array
#include <iostream>
float data[5]; // data to average and total
float total; // the total of the data items
float average; // average of the items
int main()
{
data[0] = 34.0;
data[1] = 27.0;
data[2] = 46.5;
data[3] = 82.0;
data[4] = 22.0;
total = data[0] + data[1] + data[2] + data[3] + data[4];
average = total / 5.0;
std::cout << "Total " << total << " Average " << average << "\n";
return (0);
}Total 211.5 Average 42.3
float point constant number
#include <iostream.h>
const float PI = 3.1415926;
inline float Area(const float r);
main()
{
float radius = 2.9;
cout << "The Area is " << Area(radius) << "\n";
}
float Area(const float r){
return PI * r * r;
}The Area is 26.4208
Local Float Variables and Parameters: convert the temperature in Fahrenheit to Celsius
#include <iostream>
float Convert(float);
int main()
{
using namespace std;
float TempFer = 100.00;
float TempCel;
TempCel = Convert(TempFer);
cout << TempCel << endl;
return 0;
}
float Convert(float TempFer)
{
float TempCel;
TempCel = ((TempFer - 32) * 5) / 9;
return TempCel;
}Read float point numbers from keyboard and save them to a float array
#include <iostream>
using namespace std;
int main()
{
float temp[5];
cout << "float number \n";
cin >> temp[0];
cout << "float number \n";
cin >> temp[1];
cout << "float number \n";
cin >> temp[2];
cout << "float number \n";
cin >> temp[3];
cout << "float number \n";
cin >> temp[4];
cout << temp[0] << ", " << temp[1] << ", "<< temp[2] << ", "<< tem
p[3] << ", ";
cout << temp[4] << endl;
return 0;
}float number
123.123
float number
.123.123
float number
float number
123.123.
float number
123.123, 0.123, 0.123, 123.123, 7.93782e+033
Tests whether two floating-point numbers are approximately equal.
#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;
bool approx_equal(double x, double y)
{
const double EPSILON = 1E-14;
if (x == 0) return fabs(y) <= EPSILON;
if (y == 0) return fabs(x) <= EPSILON;
return fabs(x - y) / max(fabs(x), fabs(y)) <= EPSILON;
}
int main()
{
double x;
cout << "Enter a number: ";
cin >> x;
double y;
cout << "Enter another number: ";
cin >> y;
if (approx_equal(x, y))
cout << "The numbers are approximately equal.\n";
else
cout << "The numbers are different.\n";
return 0;
}Type Conversion: from float to double
#include <iostream>
using namespace std;
int main() {
int count = 7;
float avgWeight = 155.5F;
double totalWeight = count * avgWeight;
cout << "totalWeight=" << totalWeight << endl;
return 0;
}
