Memset 3 F

There is no fixed way to represent Infinity. The first option that might come to our mind is 0x7f ff ff ff = 2^31 - 1 = 2,147,483,647 which is the maximum value of 32-bit int.

This choice has one issue -- when adding Infinity with another number, you will get overflow error.

A better choice is 0x3f 3f 3f 3f = 1,061,109,567.

• It is of the same order of magnitude as 0x7f ff ff ff but twice of it is still within the range of int.

• When using memset to initialize an array of int, since memset is filling values as unsigned char, memset(A, 0x3f, sizeof(A)) will perfectly fill 0x3f 3f 3f 3f into the array.

Reference

• https://www.kawabangga.com/posts/1153