what 's the precision of 'double'?

[blackswift]

hello,

program:
double x;
scanf("%lf", &x);
printf("%lf\n", x);

input:
3.14159265358979

output:
3.141593 (GCC 4.0.1 & visual c++ 6.0)

it seems that double has the same precision as float.

can some one tell me why ?

thanks in advance!!

 

[Rolf Magnus]

hello,

program:
double x;
scanf("%lf", &x);
printf("%lf\n", x);

Leave out the l prefix on printf.

input:
3.14159265358979

output:
3.141593 (GCC 4.0.1 & visual c++ 6.0)

printf rounded the output to 6 digits, since you didn't specify anything
else. This has nothing to do with the precision of double.

it seems that double has the same precision as float.

They might or might not have the same precision. The C++ standard only
defines minimum requirements for those types.