Different Swap techniques

Using a TEMPORARY variable:

int a = 10, b = 20;
int temp = 0;

temp = a;
a = b;
b = temp;

Without using a temporary variable:

int a = 10, b = 20;

a = a + b; // ( a = 30 )
b = a - b; // ( b = 10 )
a = a - b; // ( a = 20 )

In one line:

int a = 10, b = 20;

a = a + b - ( b = a );