The lost declaration says that, *mat is an array of int of size 5. So, mat is a pointer to an array of integers of size 5. So, here is the difference and we will argue that the fourth definition is essentially what we want and we will see this in a greater detail.
शेवटच्या डिक्लेरेशन मध्ये *mat हा अ ॅरे ऑफ इंटीजर्स ज्याची साईझ पाच आहे.