Question

Write a void function using two type int call-by-reference parameters that swaps the values in the arguments. Be sure to include testable pre and post conditions. .

Answer 1

Answer:

Please copy the C++ code inluded. It's better to open it with an Integrated Development Environment of your choice.

Th C++ code includes explanatory comments (after "//"). You may run it on on step by step basis.

The void function code follows:

void swapFunction(int & a, int & b) {    // receives 2 references (&) as  a and b

int c = a;                                  // saves a's value (actually first's) to local variable c

a = b;                                      // assigns b's value (actually second's) to a (actually first's)

b = c;                                      // assigns to b (actually second) from c

}

Main function:

using namespace std;                        // Assumes "std::" prefix for "cin" and "cout"    

int main() {                                // Main program unit

int first,second;                           // We must declare 2 variables to store 2 int values (data input)

cout << "First value:"; cin >> first;       // Reads first value after a little message

cout << "Second value:"; cin >> second;     // Reads second value after a little message

swapFunction(first,second);                 // Swap function call sends first's and second's references

cout << "First value:" << first << endl;    // Displays new first value

cout << "Second value:" << second << endl;  // Displays new second value

return 0;                                   // Success exit returns 0

}

Explanation: The testable code is included as main function

• It declares 2 int variables to store input data
• Reads the input data
• Calls swapFunction to swap values stored
• Displays exchanged values