What is ment by swapping in c

Answer 1

It could be one of several things like interchanging the values of two variables. The term is also sometimes used when data is written by the OS from memory into disk.

Answer 2

I never heard of something special like swapping in C, but maybe you mean swapping of two values?
Swapping values of a and b could look like this:
int a = 10;
int b = 20;
int c;
c = a;
a = b;
b = c;
// a == 20, b == 10