Increment and Decrement Operators in C Language

In addition to the usual `-', C also has two other interesting unary operators, `++' (increment) and `--' (decrement). Suppose we want to count the lines in a file.
main( )
{
int c,n;
n = 0;
while( (c=getchar( )) != '\0' )
if( c == '\n' )
++n;
printf("%d lines\n", n);
}
++n is equivalent to n=n+1 but clearer, particularly when n is a complicated expression. `++' and `--' can be applied only to int's and char's (and pointers which we haven't got to yet).
The unusual feature of `++' and `--' is that they can be used either before or after a variable. The value of ++k is the value of k after it has been incremented. The value of k++ is k before it is incremented. Suppose k is 5. Then
x = ++k;
increments k to 6 and then sets x to the resulting value, i.e., to 6. But
x = k++;
first sets x to to 5, and then increments k to 6. The incrementing effect of ++k and k++ is the same, but their values are respectively 5 and 6. We shall soon see examples where both of these uses are important.