I need help geting my program to work properly?

[Mitchel]

I don't know exactly whats wrong, my program works, but, I need it to be able to go all the up to "2 to the power of 295 is 6.36574E+88" but my program gives 31 a negitive answer "2 to the power of 31 is -2147483648" then it gives 0 for the rest of the answers "2 to the power of 32 is 0" ect. I have been working ont this program for 4 days. I've had several other problems but this is the only one that I cant figure out. Can you please help me?

 // File Name: PowerOf2.java
// Name of Creator: MITCHEL WRIGHT
// Date Started: 12-04-2006
// Date Finished: 12-04-2006
// Purpose: to find "2 to the power of #=____"
// Assignment: Create a program that will tell you
// "2 to the power of 0 is 1"-"2 to the power of 295 is 6.36574E+88"
//===============PowerOf2.java======================
 public class PowerOf2 
{
public static void main (String args[])
{ int intarray[]= new int [296];
for (int I=0;I<=295; I++)
{ 
intarray[i]=1;
for (int p=0; p<I;p++)
{ 
intarray[i]*=2; 
}
for (int i=0; i<1; i++)
System.out.println("2 to the power of "+I+" is " + intarray[i]);
}
}
}
 

[mharrison]

I don't know exactly whats wrong, my program works, but, I need it to be able to go all the up to "2 to the power of 295 is 6.36574E+88" but my program gives 31 a negitive answer "2 to the power of 31 is -2147483648" then it gives 0 for the rest of the answers "2 to the power of 32 is 0" ect. I have been working ont this program for 4 days. I've had several other problems but this is the only one that I cant figure out. Can you please help me?

 // File Name: PowerOf2.java
// Name of Creator: MITCHEL WRIGHT
// Date Started: 12-04-2006
// Date Finished: 12-04-2006
// Purpose: to find "2 to the power of #=____"
// Assignment: Create a program that will tell you
// "2 to the power of 0 is 1"-"2 to the power of 295 is 6.36574E+88"
//===============PowerOf2.java======================
 public class PowerOf2 
{
public static void main (String args[])
{ int intarray[]= new int [296];
for (int I=0;I<=295; I++)
{ 
intarray[i]=1;
for (int p=0; p<I;p++)
{ 
intarray[i]*=2; 
}
for (int i=0; i<1; i++)
System.out.println("2 to the power of "+I+" is " + intarray[i]);
}
}
}
 

Hey man,

Easiest way of solving your problem is to use Math.pow

 
// File Name: PowerOf2.java
// Name of Creator: MITCHEL WRIGHT
// Date Started: 12-04-2006
// Date Finished: 12-04-2006
// Purpose: to find "2 to the power of #=____"
// Assignment: Create a program that will tell you
// "2 to the power of 0 is 1"-"2 to the power of 295 is 6.36574E+88"
//===============PowerOf2.java======================  
public class PowerOf2 
{
    public static void main (String args[])
    {
        for (int i=0; i < 296; i++) {
            System.out.println("2 to the power of "+i+" is " + getPower(i));
        }
    }
 
    public static double getPower(double i) {
        return Math.pow(2,i);
    }
 
}
 

May I suggest reading up on this:

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Math.html#pow(double,%20double)

mharrison

[horace1]

In Java the int data type is a 32-bit signed two's complement integer, i.e. minimum value of -2,147,483,648 and a maximum value of 2,147,483,647 (inclusive), therefore it won't represent a number of the magnitude 6.36574E+88. Change your program to use double, e.g.

 double intarray[]= new double [296];
 

The double data type is a double-precision 64-bit IEEE 754 floating point number and will represent the numeric range you require.
for example, running your program using double the output is
2 to the power of 0 is 1.0
2 to the power of 1 is 2.0
2 to the power of 2 is 4.0
2 to the power of 3 is 8.0
......
2 to the power of 292 is 7.957171782556586E87
2 to the power of 293 is 1.5914343565113173E88
2 to the power of 294 is 3.1828687130226345E88
2 to the power of 295 is 6.365737426045269E88