Thread: A logic error in my program

Code:

/*To find out the value in the array that the sum of all elements of the same number is the largest*/
/* Can anyone tell me what the logic error is? Thanks. */
int findMaxValue(int arr[], int n){ //n = number of elements in array
    int ans=0;
    int maxValue = 0;
    int temp[80]; //maximum of array lenth is 80
    int i,j;
    
    for(i=0; i<n; i++){
        for(j=1; j<100; j++){ //the value in array is from 0 to 100
            if(arr[i] ==  j)
                temp[j] += j;
        }
    }
    for (j=1; j<100; j++){
        if(temp[j] > maxValue){
            maxValue = temp[j];
            ans = j;
        }
    }
    return ans;
}
//Thank you.

Welcome to the forum, 20120903!

So if the array had:

7 three's, 3 sixes, and 2 ten's, you want the program to calculate that it's the 7 three's that have the greatest value, right?

I don't see logic for that. Maybe:

in an array, count up how many of each number, you have:

Code:

for(i=0;i<n;i++)
   array[array[i]]++;

Which just tells you you have X number of three's, and Y number of four's, etc. (Obviously, this is bogus unless the array[] values are set to zero, first!!

Now go back through the array values you just calculated, and figure out the max. In pseudo code:

Code:

int max = 0;
for(each number in the array) {
   multiply the value in the array, by i
   if the result is > max
      max = result
}

There are other ways to do this, but this is what I'd suggest.

Thank you for both of your suggestion.
Let's take 7 three's, 3 sixes, and 2 ten's to explain my code.
In the first loop, we can get temp[3]=21, temp[6]=18 and tmp[10]=10 as result.
In the second loop, we obtain maxValue = 21 and the answer should be 3.
I don't know why I can't get the correct result.

Originally Posted by 20120903

I don't know why I can't get the correct result.

You don't initialise your temp array thus it contains random values from INT_MIN to INT_MAX (these are the lower and upper limits for an integer on your computer). It's very likely that any element has a higher value than 21 and that's why you get the wrong index.

You should change temp to

Code:

int temp[100] = { 0 };

so that every element is set to 0.

Bye, Andreas

My code works now. Thank you.