C++ bootcamp · Lab 32

Swap with references

mediumReferences12 minLesson: References

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QuestionHint and solution stay closed until you open them

Complete swap so it exchanges two ints using references (not pointers).

main reads a and b, calls swap(a, b), and prints them. After the call, print the original b then the original a.

Input. Two integers a and b.

Output. b then a, separated by a space.

Constraints

  • You must change the values through the references. Do not only print in reverse order inside main.

Examples

Example 1
Input
7 2
Output
2 7
Example 2
Input
0 9
Output
9 0
Hint
  1. void swap(int& a, int& b) — the & means an alias, not an address you must dereference.
  2. int tmp = a; a = b; b = tmp;
Show correct code

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#include <iostream>

void swap(int& a, int& b) {
  int tmp = a;
  a = b;
  b = tmp;
}

int main() {
  int a, b;
  std::cin >> a >> b;
  swap(a, b);
  std::cout << a << " " << b << "\n";
  return 0;
}
main.cppC++17 · g++ · Ctrl + Enter runs
ResultIdle
Run to see output. Check grades the tests.