Lesson 7 Source Code

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Lesson 7 Video

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Lesson 7: the float and double types

NOTE: for a fast copy, follow these steps in order:

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(The result should be that all the text inside the text box lights up in blue)
Hit Ctrl + C (Nothing significantly happens that is visible) and now its copied to the clipboard and your ready to paste it anywhere 

you wish



Examples of the float types

The float type will display up to six significant figures
#include <iostream>
using namespace std;

int main()
{
 float weight = 2.2468481268548972;
 cout << weight;
 cin.get();
 return 0;
}

#include <iostream>
using namespace std;

int main()
{
 float weight = 295.2468481268548972;
 cout << weight;
 cin.get();
 return 0;
}


The value will be dislayed in scientific notation when necessary.
#include <iostream>
using namespace std;

int main()
{
 float weight = 548123846512354;
 cout << weight;
 cin.get();
 return 0;
}

#include <iostream>
using namespace std;

int main()
{
 float weight = .00000000054812358;
 cout << weight;
 cin.get();
 return 0;
}


The float type will display 20 million in scientific notation but the the int type will not.
#include <iostream>
using namespace std;

int main()
{
 float weight = 20000000;
 cout << weight;
 cin.get();
 return 0;
}

#include <iostream>
using namespace std;

int main()
{
 int weight = 20000000;
 cout << weight;
 cin.get();
 return 0;
}


float types do not store a lot of significant figures. Look at this code carefully. The last number printed to the screen should be 0.2 

but you will get 0.1875 when its compiled.
#include <iostream>
using namespace std;

int main()
{
 float weight = 300000.1;
 float z = 300000.1;
 float total = weight + z;
 cout << weight;
 cout << endl << total - 600000;
 cin.get();
 return 0;
}



Examples of the float types
A better version of the float type (recommended)

Now compile this code.. The correct result is displayed after changing the float types to double types.
#include <iostream>
using namespace std;

int main()
{
 double weight = 300000.1;
 double z = 300000.1;
 double total = weight + z;
 cout << weight;
 cout << endl << total - 600000;
 cin.get();
 return 0;
}