复数，cs 50，为什么 printf function 在 if 语句之外打印不同？

Question

I know it is not correct implementation for print_winner function (printf should be inside the if statment). However, I cannot figure out why printf prints names differently when placed outside if-statement?

If I place printf outside if statement, here is the code and output

Code:

// Print the winner (or winners) of the election
void print_winner(void)
{

int maximum = candidates[0].votes;
string winner = candidates[0].name;

    for (int h = 0; h < candidate_count; h++)
        {
            if (candidates[h].votes > maximum)
                {
                    maximum  = candidates[h].votes;
                }
        }

    for (int k = 0; k < candidate_count; k++)
        {
            if (candidates[k].votes == maximum)
                {
                    winner = candidates[k].name;

                }
                printf("%s\n", winner);

Output:

~/pset3/plurality/ $ ./test sonya criss ben anbu
Number of voters: 4
Vote: ben  
Vote: ben
Vote: anbu
Vote: anbu
sonya
sonya
ben
anbu

If I put printf inside if statement, here is the code and output:

Code:

// Print the winner (or winners) of the election
void print_winner(void)
{

int maximum = candidates[0].votes;
string winner = candidates[0].name;
    //Find maximum votes
    for (int h = 0; h < candidate_count; h++)
        {
            if (candidates[h].votes > maximum)
                {
                    maximum  = candidates[h].votes;
                    winner = candidates[h].name;

                }

        }
    //Find candidate with maximum votes
     for (int k = 0; k < candidate_count; k++)
        {
            if (candidates[k].votes == maximum)
                {
                    winner = candidates[k].name;

                    printf("%s\n", winner);
                }

        }

    return;
}

Output:

~/pset3/plurality/ $ ./plurality sonya criss ben anbu
Number of voters: 4
Vote: ben
Vote: ben
Vote: anbu
Vote: anbu
ben
anbu

Answer 1

in your first case the winner name you print is candidates[0].name which is sonia until if (candidates[k].votes == maximum) become true and you reassign winner , and you print candidate_count times because unconditionally in the loop.

In the second case you only print the name of the person whose votes number equals the maximum ( if (candidates[k].votes == maximum) is true), so only ben and anbu having both 2 votes being the maximum.

Because several persons can have the same number of votes it is useless to have the variable winner , you can do

// Print the winner (or winners) of the election
void print_winner(void)
{
  int maximum = candidates[0].votes; /* suppose candidate_count > 0, else initialize with -1 */
  
  //Find maximum votes
  for (int h = 1; h < candidate_count; h++) /* useless to redo at index 0 */
  {
     if (candidates[h].votes > maximum)
       maximum  = candidates[h].votes;
  }

  //Find candidate(s) with maximum votes
  for (int k = 0; k < candidate_count; k++)
  {
     if (candidates[k].votes == maximum)
       puts(candidates[k].name);
  }
}

---

From your remark

Could you elaborate why in the first case winner name is printed candidates[0].name until if (candidates[k].votes becomes true

because you initialize winner with candidates[0].name; doing:

string winner = candidates[0].name;

and you modify winner only when if (candidates[k].votes == maximum) is true:

 if (candidates[k].votes == maximum) { winner = candidates[k].name;