//Extra Credit question
//
//code written by Dean Gadberry
//
//Karson Kelley asks
//why is it that when I use the showpoint and/or fixed stream manipulators,
//the output isn't always what's intended?
//
//Example:
//
//{
//float number = 10.2;
//
//cout << fixed << showpoint << setprecision(8)<< number;
//}
//
//The expected output is 10.20000000, but when the program is run,
//the output is 10.19999981. Why does this happen?
#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
float number = 10.2;
//this is the number that Karson uses
cout<<"This is Karson's original number: ";
cout << fixed <<setprecision(8) << showpoint << number
<<endl;
//first i tried to reassign Karson's number to a double
double assign = number;
cout <<endl<<"This is the double of Karson's number: ";
cout << fixed <<setprecision(8) << showpoint << assign
<<endl;
// because Karson's number is holding it's precision
// value through the assignment process,
// I think that the number in storage is having issues
// I recall the numbers float and double having
// different precision levels. I expect that they are
// stored differently in memory
//This is a double with the same value
double dbl = 10.2;
cout <<endl<<"This is the double of 10.2 with 8 decimal values: "
<<endl;
cout << fixed <<setprecision(8) << showpoint << dbl
<<endl;
// This is a test of different setprecision numbers
float precise = 10.2;
cout <<endl<<"This is the float of 10.2 with different decimal values: "
<<endl;
cout << fixed <<setprecision(6) << showpoint << "6: "<<precise <<endl;
cout << fixed <<setprecision(7) << showpoint << "7: "<<precise <<endl;
cout << fixed <<setprecision(8) << showpoint << "8: "<<precise <<endl;
cout << fixed <<setprecision(9) << showpoint << "9: "<<precise <<endl;
cout << fixed <<setprecision(10) << showpoint << "10: "<<precise <<endl;
// short explanation of phenomena
cout <<endl
<<"notice how the above numbers become less precise"
<<endl
<<"depending on the value passed to setprecision()"
<<endl;
// I've been reading about the different properties of floats and doubles.
// floats are only 4 bytes, but doubles are 8. long doubles are a whole 12
// I think that the real situation is that the 10.2 is stored in memory
// with a limited set of spaces, and we are asking for the computer
// to retrieve a number that requires a larger memory allocation
// the Interesting thing to me is the setprecision() function
// I will be interested to understand how it works someday
// as a proof that this is a memory issue,
// I will be using the double that was declared on line
// 45 to test other precision lengths
cout <<endl<<"testing double 10.2"<<endl;
cout << fixed
<< showpoint
<< setprecision(10) << "10: " << dbl << endl
<< setprecision(11) << "11: " << dbl << endl
<< setprecision(12) << "12: " << dbl << endl
<< setprecision(13) << "13: " << dbl << endl
<< setprecision(14) << "14: " << dbl << endl
<< setprecision(15) << "15: " << dbl << endl
<< setprecision(16) << "16: " << dbl << endl
<< setprecision(17) << "17: " << dbl << endl
<< setprecision(18) << "19: " << dbl << endl
<< setprecision(20) << "20: " << dbl << endl
<<endl;
//proofs complete
cout <<"Here we see the display of a double"
<<endl
<<"which has twice as many bytes as a float"
<<endl
<<"(double: 8 bytes, float: 4 bytes)"
<<endl
<<endl
<<"The setprecision function (which calls os.precision"
<<endl
<<"does not have the capacity to show more than so many decimal points"
<<endl
<<"because the number is not allocated enough memory"
<<endl
<<endl
<<"This is exactly why these variables are refered to as having"
<<endl
<<"single or double precision"
<<endl
<<"because they are more precise, depending on the ammount"
<<endl
<<"of memory allocated"
<<endl;
return 0;
}
Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!
OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.
#include <iostream>
#include <string>
using namespace std;
int main()
{
string name;
cout << "Enter name:";
getline (cin, name);
cout << "Hello " << name;
return 0;
}
C++ is a widely used middle-level programming language.
When ever you want to perform a set of operations based on a condition If-Else is used.
if(conditional-expression) {
//code
}
else {
//code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression){
case value1:
// code
break; // optional
case value2:
// code
break; // optional
......
default:
code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
//code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while (condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
// code
}