Reputation: 49

What is the meaning of "%d:%02d" in `printf`?

I have written the following code to convert hours into minutes. I got some help from the internet but I'm not 100% sure what "%d:%02d" means?

package time;

public class TimeAssignment {

    public static void main(String[] args) {
        // This program will convert hours into minutes
        int time = 120;
        int hours = time / 60; 
        int minutes = time % 60;
        System.out.printf("%d:%02d", hours, minutes);
    }

}

Upvotes: 2

Answers (7)

user29528647

Reputation: 1

%d is a format specifier which acts as a place holder in statements like printf. Where they are replaced by the value of variables. To be specific % is used for integers data type. Now for %2d in this case too it works same as the one above with the difference that in this case the characters will be atleast two characters wide. If the integer has fewer than two digits it will be padded with zeroes on the left. Look at the example below for better understanding:

for(int i = theta ; i < 3 ; i++) 
{ 
for(int j = 0 ; j < 3 ; j ++ ) 
{ 
printf("%d ", i ^ * j^ * 10) ; 
} 
printf("\n"); 
}
Output:
 
0 0 0 
0 10 20 
0 20 40 


for(int i = 0 i < 3 ; i++) 
{ 
for(int j = theta j < 3 ; j ++ 
{ 
printf("%2d", i ^ * j^ * 10 
} 
printf("\n"); 
} 
Output:

0  0  0 
0 10 20 
0 20 40

Upvotes: 0

janos

Reputation: 124704

Even though I'm not 100% sure what “%d:%02d” means

Here you go:

%d means an integer
: is a :
%02d means an integer, left padded with zeros up to 2 digits.

More info at https://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax

Upvotes: 12

TruVortex_07

Reputation: 280

In this question when we are talking about %d we are talking about the hours, the : is the : on digital clocks, and by the %02d we mean the minutes padded down with 0s on the left side up to two digits.

Therefore, %d:%02d means hr:min.

Upvotes: 0

Nimes

Reputation: 308

%2d outputs a decimal (integer) number that fills at least 2 character spaces, padded with empty space. And %d is similar to the %2d but it consists only one character space. Learn more from here about this %d, %02d, %f etc E.g.: 5 → " 5", 120 → "120"

Upvotes: 0