C++ Vectors: Finding Values in vectors

[needOfHelpCMath]

I would like some help or guide to if i am going on the right track on my program ***Set numMatches to the number of elements in userValues (having NUM_VALS elements) that equal matchValue. Ex: If matchValue = 2 and userValues = {2, 2, 1, 2}, then numMatches = 3. ***

#include <iostream>
#include <vector>
using namespace std;

int main() {
   const int NUM_VALS = 4;
   vector<int> userValues(NUM_VALS);
   int i = 0;
   int matchValue = 0;
   int numMatches = -99; // Assign numMatches with 0 before your for loop

   userValues.at(0) = 2;
   userValues.at(1) = 2;
   userValues.at(2) = 1;
   userValues.at(3) = 2;

   matchValue = 2;

   numMatches= userValues.at(0);
   for (i = 0; i < NUM_VALS; ++i) 
   {
     cin >> userValues.at(i);
   }
         
   for (i = 0; i < NUM_VALS; ++i) {
      numMatches = numMatches + userValues.at(i);
   }
   

   cout << "matchValue: " << matchValue << ", numMatches: " << numMatches << endl;

   return 0;
}

**MY TEST**

Testing matchValue = 2,
userValues = {2, 2, 1, 2}
Expected value: 3
Your value: 9

 

[MarkFL]

You want something like:

numMatches= 0;
for (i = 0; i < NUM_VALS; i++) 
{
	if (userValues.at(i) == matchValue)
	{
		numMatches++;
	}
}

You see, in your code, you first assign the value of [m]userValues.at(0)[/m] to [m]numMatches[/m], which is 2, and then in your second for loop, you add each of the values in the array to [m]numMatches[/m], so you wind up with:

[m]numMatches = 2 + 2 + 2 + 1 + 2 = 9[/m]

As you can see in the code I wrote, we initialize [m]numMatches[/m] to zero before the loop, and then we check each element of the array to see if it is equal to [m]matchValue[/m], and if it is, then we increment [m]numMatches[/m], so that we get a count of the number of elements that match.

Does this make sense?

 

[needOfHelpCMath]

You want something like:

numMatches= 0;
for (i = 0; i < NUM_VALS; i++) 
{
	if (userValues.at(i) == matchValue)
	{
		numMatches++;
	}
}

You see, in your code, you first assign the value of [m]userValues.at(0)[/m] to [m]numMatches[/m], which is 2, and then in your second for loop, you add each of the values in the array to [m]numMatches[/m], so you wind up with:

[m]numMatches = 2 + 2 + 2 + 1 + 2 = 9[/m]

As you can see in the code I wrote, we initialize [m]numMatches[/m] to zero before the loop, and then we check each element of the array to see if it is equal to [m]matchValue[/m], and if it is, then we increment [m]numMatches[/m], so that we get a count of the number of elements that match.

Does this make sense?

Yes! it does! I am so horrible at understanding what the programs wants...any tips for me so that i can understand what the programs wants. Thank you it made a lot of sense!

 

[MarkFL]

Understanding the expected output, and how to get it generally comes with practice. Coding can be extremely rewarding, and it can be extremely frustrating at the same time. :)