Why does alert(0.-5) print -5?












6















Suppose I write 0.5 as 0.-5 in unexpected way, but it can still run, my question is , what does "0." in "0.-5" do so that it can still run and prints -5?



I also tried alert(0.-5+1) , which prints -4, does javascript ignores "0." in "0.-5"?






javascript numbers







share|improve this question




















  • 2





    0. is like 0.0. Or just 0.

    – Ry-♦
    2 hours ago


















6















Suppose I write 0.5 as 0.-5 in unexpected way, but it can still run, my question is , what does "0." in "0.-5" do so that it can still run and prints -5?



I also tried alert(0.-5+1) , which prints -4, does javascript ignores "0." in "0.-5"?






javascript numbers







share|improve this question




















  • 2





    0. is like 0.0. Or just 0.

    – Ry-♦
    2 hours ago
















6












6








6


1






Suppose I write 0.5 as 0.-5 in unexpected way, but it can still run, my question is , what does "0." in "0.-5" do so that it can still run and prints -5?



I also tried alert(0.-5+1) , which prints -4, does javascript ignores "0." in "0.-5"?






javascript numbers







share|improve this question
















Suppose I write 0.5 as 0.-5 in unexpected way, but it can still run, my question is , what does "0." in "0.-5" do so that it can still run and prints -5?



I also tried alert(0.-5+1) , which prints -4, does javascript ignores "0." in "0.-5"?






javascript numbers




javascript numbers






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 28 mins ago









Charlie H

9,03342550




9,03342550










asked 2 hours ago









mmmaaammmaaa

2,2231311




2,2231311








  • 2





    0. is like 0.0. Or just 0.

    – Ry-♦
    2 hours ago
















  • 2





    0. is like 0.0. Or just 0.

    – Ry-♦
    2 hours ago










2




2





0. is like 0.0. Or just 0.

– Ry-♦
2 hours ago







0. is like 0.0. Or just 0.

– Ry-♦
2 hours ago














2 Answers
2






active

oldest

votes


















6














Trailing digits after a . are optional:






console.log(0. === 0);





So



0.-5


evalutes to



0 - 5


which is just -5. Similarly,



0.-5+1


is



0 - 5 + 1


which is



-5 + 1


or -4.






share|improve this answer































    0














    In JS you can express a number with optional decimal point. 



    x = 5.;    //5
    
x = 5. + 6.   //11





    share|improve this answer























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      2 Answers
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      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      6














      Trailing digits after a . are optional:






      console.log(0. === 0);





      So



      0.-5


      evalutes to



      0 - 5


      which is just -5. Similarly,



      0.-5+1


      is



      0 - 5 + 1


      which is



      -5 + 1


      or -4.






      share|improve this answer




























        6














        Trailing digits after a . are optional:






        console.log(0. === 0);





        So



        0.-5


        evalutes to



        0 - 5


        which is just -5. Similarly,



        0.-5+1


        is



        0 - 5 + 1


        which is



        -5 + 1


        or -4.






        share|improve this answer


























          6












          6








          6







          Trailing digits after a . are optional:






          console.log(0. === 0);





          So



          0.-5


          evalutes to



          0 - 5


          which is just -5. Similarly,



          0.-5+1


          is



          0 - 5 + 1


          which is



          -5 + 1


          or -4.






          share|improve this answer













          Trailing digits after a . are optional:






          console.log(0. === 0);





          So



          0.-5


          evalutes to



          0 - 5


          which is just -5. Similarly,



          0.-5+1


          is



          0 - 5 + 1


          which is



          -5 + 1


          or -4.






          console.log(0. === 0);





          console.log(0. === 0);






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 hours ago









          CertainPerformanceCertainPerformance

          88.8k154876




          88.8k154876

























              0














              In JS you can express a number with optional decimal point. 



              x = 5.;    //5
              
x = 5. + 6.   //11





              share|improve this answer




























                0














                In JS you can express a number with optional decimal point. 



                x = 5.;    //5
                
x = 5. + 6.   //11





                share|improve this answer


























                  0












                  0








                  0







                  In JS you can express a number with optional decimal point. 



                  x = 5.;    //5
                  
x = 5. + 6.   //11





                  share|improve this answer













                  In JS you can express a number with optional decimal point. 



                  x = 5.;    //5
                  
x = 5. + 6.   //11






                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 1 hour ago









                  Charlie HCharlie H

                  9,03342550




                  9,03342550






























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