在scanf函数的格式字符串中，换行符的意义是什么？

Question

#include<stdio.h>
int main()
{
int a,b;
printf("enter two numbers ");
scanf("%d \n%d",&a,&b);
printf("%d  %d",a,b);
return 0;
}

when I give inputs like 3 and 5 , then the issue is that even if I give inputs without any newline character in between them then also the scanf function scans the input value , but in the formal string I have stated that the next input should be scanned after a newline character so how can the next input be scanned just after some few whitespaces .

Answer 1

White-space in the scanf format string tells scanf (and family) to read and ignore white-space in the input. It doesn't matter what kind of white-space character you use in the format: Space, newlines and tabs are all the same.

However, you don't actually need it for all formats. most scanf formats automatically reads and ignore leading white-space, including the "%d" format.

Answer 2

The " \\n" in the "%d \\n%d" format string will "eat" all whitespace characters as defined by isspace , including newlines.

To force reading the integers off separate lines, use this instead:

if(scanf("%d%*[^\n]\n%d",&a,&b) != 2) return EXIT_ERROR;