CS210 Lab: Stacks Postlab Answers

Postlab Answers:

For each of the permutations below, give a code fragment (as in the above example) to output the permutation
or provide a brief explanation of why the permutation cannot be produced.
  1. "xyz" 
    2. 		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
  2. "xzy" 
    3. 		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		cin >> ch;  mystack.push(ch);
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		ch = mystack.top();   mystack.pop();   cout << ch;
  3. "yxz" 
    4. 		cin >> ch;  mystack.push(ch);
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		ch = mystack.top();   mystack.pop();   cout << ch;
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
  4. "yzx" 
    5. 		cin >> ch;  mystack.push(ch);
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		ch = mystack.top();   mystack.pop();   cout << ch;
  5. "zxy" 
    6. 		cannot print z first and have x on top of y
  6. "zyx" 
    7. 		cin >> ch;  mystack.push(ch);
		cin >> ch;  mystack.push(ch);
		cin >> ch;  mystack.push(ch);
		ch = mystack.top();   mystack.pop();   cout << ch;
		ch = mystack.top();   mystack.pop();   cout << ch;
		ch = mystack.top();   mystack.pop();   cout << ch;
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