make a table for [closed] - tdd

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Closed 9 years ago.
math.sqrt(X). the following is the table for it
math.sqrt(X). the following is the table for it
public class SqRoots
{ static final int N = 10; // How many square roots to compute.
public static void main ( String [] args )
{
// Display a title
System.out.println( "\n Square Root Table" );
System.out.println( "-------------------" );
for ( int i = 1; i <= N; ++i ) // loop
{
// Compute and display square root of i
System.out.println( " " + i + ":\t" + Math.sqrt( i ) );
}
}
}

Answer 1

Here's what I'd do:
public class SqrtTester {
public static final int MAX_VALUES = 100;
public static void main(String [] args) {
int numValues = ((args.length > 0) ? Integer.valueOf(args[0]) : MAX_VALUES);
double x = 0.0;
double dx = 0.1;
for (int i = 0; i < numValues; ++i) {
double librarySqrt = Math.sqrt(x);
double yourSqrt = SqrtTester.sqrt(x);
System.out.println(String.format("value: %10.4f library sqrt: %10.4f your sqrt: %10.4f diff: %10.4f", x, librarySqrt, yourSqrt, (librarySqrt-yourSqrt)));
x += dx;
}
}
public static double sqrt(double x) {
double value = 0.0;
// put your code to calc square root here
return value;
}
}

Answer 2

The simple part first: "for every value of x from 0 to 10 in increments of 1" means
for(int x = 0; x < 10; x++) {
// do something with x
}
The harder part: "build a table"
I would create a class to hold a "row" of data:
public class Result {
private int x;
private double mathSqrt;
private double mySqrt;
public double diff() {
return mySqrt - mathSqrt;
}
// getters and other methods as you need
}
Then use the loop over some code to create Result objects for every x value and put it all together.