----forgot to add list as cc------ Hi Kaushik, any extra non-whitespace, non "%" characters are matched against the input given from stdin - if they match, it is ignored and if it doesn't match, no further input is taken. In case of your second scenario, when you specify "p:%d" as string, the program expects the input to be of the format "p:<some number>" but since you give 100 as the input, no value is assigned to the variable p (you can check the return value of scanf - its zero) and hence, whatever junk value is in variable p, it is used for further calculation. With the second scenario, try giving the input as "p:100" and then p should get value 100 as expected... Hope that helps. Aneesh On Wed, Jul 29, 2009 at 7:48 PM, RAM_LOCK <Kaushik.Sarkar@xxxxxxxxxx> wrote: > > Hi, > In the second scenario what value is it printing when i have given extra > parameter in scanf? > Does it vary from compiler to compiler? > > Scenario : I > ------------- > root@kaushik_Fedora11 ~/C/LET_US_C/ch-1> cat simple-interest.c > #include <stdio.h> > > void main () > { > int p; > float i=0; > printf ("enter the principal amount\n"); > scanf ("%d",&p); > i = (p*5*5)/100; > printf ("Interterest is : %f\n",i); > } > root@kaushik_Fedora11 ~/C/LET_US_C/ch-1> ./a.out > enter the principal amount > 100 > Interterest is : 25.000000 > > > Scenario : II > ------------- > > cat simple-interest.c > #include <stdio.h> > > void main () > { > int p; > float i=0; > printf ("enter the principal amount\n"); > scanf ("p:%d",&p); > i = (p*5*5)/100; > printf ("Interterest is : %f\n",i); > } > root@kaushik_Fedora11 ~/C/LET_US_C/ch-1> ./a.out > enter the principal amount > 100 > Interterest is : -9321198.000000 > > -- > View this message in context: http://www.nabble.com/What-compiler-is-doing-when-we-pass-unnecessary-parameters-in-scanf-tp24719839p24719839.html > Sent from the linux-c-programming mailing list archive at Nabble.com. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html