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## Easy Java Simulations (2001- ) => Questions related to EJS => Topic started by: lookang on March 28, 2009, 11:10:47 am

 Title: how to make a Ejs way to recognize that a number is 10,100,1000 etc Post by: lookang on March 28, 2009, 11:10:47 am how to make a Ejs way to recognize that a number is 10,100,1000 etcif number is 1000 to 9999 , how to display 1000 ?so if a number is 100 to 999, how to display 100 ?if the number is 10 to 99, how to display 10number 0 to 9 display as 1 ?thanks! Title: Re: how to make a Ejs way to recognize that a number is 10,100,1000 etc Post by: Fu-Kwun Hwang on March 28, 2009, 10:22:38 pm Your question is not limited to EJS. It is a general question related to mathematics and programming.3≦log10(x)<4 if 10002≦log10(x)<3 if 100However, java did not provide function for log10(x).It only provide nature log, i.e. ln(x).log10(x)= loge(x)/loge(10)and Math.pow(a,b) will return abThe following formula should give you what you want.Code:y=(int)(Math.pow(10,(int)(Math.log(x)/Math.log(10.)+1.e-8)));1.e-8 was added due to possible numerical error. Title: Re: how to make a Ejs way to recognize that a number is 10,100,1000 etc Post by: lookang on March 30, 2009, 10:24:15 am excellent help.Code:scaffold=(int)(Math.pow(10,(int)(Math.log(i2)/Math.log(10.)+1.e-8)));i assign my own variables ( scaffold and i2) substitution to modify.thanks for the programming tip.i read a bit before on Math.pow(a,b) which is abso what you suggested is 10(i2/log10 +1.e-8) Title: Re: how to make a Ejs way to recognize that a number is 10,100,1000 etc Post by: Fu-Kwun Hwang on March 30, 2009, 10:37:50 am What I suggest is 10(log(i2)/log(10))+1.e-8