Fast and easy way to do some multiplications

Most of computers have the shift left instruction.

Shifting the bits by “x” positions to left, is equivalent to multiplication by x^2.

In this case…

int a = 4;
int b = 0;
b = a<<1;
/* Now, b value is 8 */
b = a<<2;
/* Now, b value is 16 */

That’s all folks!