Consider the following code:
#include<stdio.h>
int main() {
int i=3, j=4;
scanf("%d c %d",&i,&j);
printf("%d %d",i,j);
return 0;
}
It works if I give 2c3 or 2 c 3 or 2c 3 as input if I have to change the value of variables. What should I do if I want the user to enter the same pattern as I want means if %dc%d then only 2c3 is acceptable and not 2 c 3 and vice versa if it is %d c %d?
If you want to accept 1c2 but not 1 c 2, use the pattern without the space:
scanf("%dc%d", &x, &y);
If you want to accept 1c2 and 1 c 2 (and also 1 \t \t c \t 2 etc), use the pattern with the space:
scanf("%d c %d", &x, &y);
If you want to accept 1 c 2 but not 1c2, add a fake string containing whitespace:
scanf("%d%*[ \t]c%*[ \t]%d", &x, &y);
Here the format string %[ \t] would mean "read a string that contains any number of space and tab characters"; but using the additional *, it becomes "expect a string that contains any number of space and tab characters; then discard it"