Exercise 10/23/03
Objective: Learn to hand trace C++ program execution.
For each of the function calls in the following program, construct a table that shows the changes of every
variable during the execution of the function, and determine the function’s return value. Finally, show the final
output of the program. Do all these without using the computer.
#include <iostream>
using namespace std;
int mystery1(int n, int k);
int mystery2(int m, int n);
int mystery3(int n);
int mystery4(int n, int d);
double mystery5(double x, int n);
int main()
{
cout << "mystery1(10, 4) = " << mystery1(10, 4) << endl;
cout << "mystery2(315, 756) = " << mystery2(315, 756) << endl;
cout << "mystery3(123456) = " << mystery3(123456) << endl;
cout << "mystery4(123, 12) = " << mystery4(123, 12) << endl;
cout << "mystery5(3.0, 5) = " << mystery5(3.0, 5) << endl;
return 0;
}
int mystery1(int n, int k)
{ assert(0 <= k && k <= n && n <= 33);
int y = 1;
for (int i=1; i<=k; i++, n--)
y = y*n/i;
return y;
}
int mystery2(int m, int n)
{ assert(m > 0 && n > 0);
do {
while (m <= n)
n = n - m;
int temp = m;
m = n;
n = temp;
} while (m > 0);
return n;
}
