Didn't understand when should I use *

Question

Hey! Can someone please explain to me why would I ever use *?
In the example code they don't assign a variable to the %*f so I added it myself (both to the scanf and printf) but its still doesn't print it at the end instead my output is a bunch of numbers

My input is: 12 3 4.5 abcde
https://code.sololearn.com/cyfKLMJoBPOO/?ref=app

Answer 1

Quoted from
http://www.cplusplus.com/reference/cstdio/scanf/

"An optional starting asterisk indicates that the data is to be read from the stream, but ignored (i.e. it is not stored in the location pointed by an argument."

You used %*f specifier which means the 3rd input (float number) will be read from the stream, but its value will not be stored into variable <z>.

I got totally different outputs during tests, seems to me that the first 4 characters (size of float) of "elephant" that was supposedly for <text> was rather read and stored as float number into <z>.

12 34 5.7 elephant
↓ ↓ ↓ ↓
<x> <y> <skipped> <z>

Hth, cmiiw

Answer 2

Thanks! So why would I use it? If I can't use the value then what good is it

Answer 3

In this snippet we are reading coordinates in "x,y" format, the x and y are integer, but we want to ignore the comma in between those x & y values, so we read it, but we don't use it, because we only want the x & y.

#include <stdio.h>

int main()
{
char input[23];
int x, y;

puts("Enter coordinates:\nEnter 0, 0 to quit.\n");
while (1)
{
scanf ("%d%*c%d", &x, &y);
if (!x && !y) break;
printf ("Coordinate X:%d Y:%d\n\n", x, y);
}
return 0;
}