Java: count occurrences in 2d array and output result in 1d array

Question

I'm start to learn Java programming language and try to solve given task

I'm try to finish method to count occurrences in 2d array and output result in 1d

public static int[] histogram(int[][] a, int high) {
    // Please write your code after this line
    // init new array 
    int numOfRows = a.length;
    int numOfCols = a[0].length;
    int[] retVal = {};
    //main loop
    for (int o = 0; o < high; o++){
        //System.out.println(o);
        // go trough rows 
        for(int row = 0; row < numOfRows; row++ ){
            // check for colum values
            int count = 0;
            for(int col = 0; col < numOfCols; col++ ){

                if(a[row][col] = o ){
                    count++;
                }

            }
            retVal[o] = count; // Fixed typo 

        }


    }


    return retVal;
}

this is my method

I'm using BlueJ IDE for compiling and when i compile i get error "Incompatible types " for this line

if(a[row][col] = o )

i don't get it why i get error, in my opininon a[row][col] is int type ? and o is int type too.

Thanks

Can I suggest that o is a not a good choice of variable name? It looks far too much like 0 at a glance (in certain fonts). — Andy Turner
– Andy Turner, Commented Mar 15, 2016 at 20:16
thanks for suggestion this is anyway all not finished i'll keep your suggestion on my mind for final code. — Sile Cetoy
– Sile Cetoy, Commented Mar 15, 2016 at 20:27

Rishi · Accepted Answer · 2016-03-15 20:09:42Z

1

if(a[row][col] = o )

use == operator for checking equality, so finally it should be

if(a[row][col] == o )

answered Mar 15, 2016 at 20:09

Rishi

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2 Comments

Sile Cetoy Over a year ago

uhm. i that is it, i constantly think about operators and i miss this :(

Rishi Over a year ago

@SileCetoy : always remember that == results in boolean

Yassin Hajaj · Accepted Answer · 2016-03-15 20:08:34Z

0

if(a[row][col] = o ) // Assignment Operator

should be

if(a[row][col] == o ) // Equality evaluator

Operators JavaDoc

answered Mar 15, 2016 at 20:08

Yassin Hajaj

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