1. defines a function called gcd, which accepts two integer parameters A and B. This function will calculate the greatest common divisor of A and B by division.
2. In the function body, first check whether b is 0. If yes, then the greatest common divisor is a, because in the process of division, if the remainder is 0, then the divisor is the greatest common divisor.
3. If b is not 0, call the gcd function recursively, and take b and a% b as new parameters. Here we use the recursive nature of division, that is, for two integers A and B, their greatest common divisor is equal to the greatest common divisor of B and A% B. Through recursive call, we can divide the current number by a smaller number until the remainder is 0, and then the greatest common divisor is the current divisor.
4. In the main function, first prompt the user to enter two integers. Then use the scanf function to read these two integers from the standard input and store them in variables num 1 and num2.
5. Then call the gcd function and pass in num 1 and num2 as parameters to get their greatest common divisor and store it in the variable result.
Application of stage division;
1. cryptography: in cryptography, division and transformation are often used to calculate the greatest common divisor of two integers, thus obtaining some key parameters in cryptography. For example, in RSA public key cryptosystem, the greatest common divisor is needed, and the greatest common divisor of two numbers can be obtained efficiently by division, and then other parameters can be calculated.
2. Computer science: Classification by stages is also widely used in computer science. For example, when calculating the greatest common divisor of two integers, alternating division provides a simple and effective method. In addition, commutation division can also be used to solve other problems, such as finding the largest subsequence sum in an array.
3. Mathematics: Division is also widely used in mathematics. For example, in solving some mathematical problems, division by turns can provide an effective recursive algorithm, thus simplifying the problem-solving process. In addition, division can also be used to prove some mathematical theorems, such as Euclid's theorem.