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2017-09-25

posted Sep 25, 2017, 9:51 AM by Samuel Konstantinovich   [ updated Sep 25, 2017, 10:08 AM ]
 Exam Friday. All of Java so far. Not including objects. (We start them soon)-Go over all problems there was difficulty solving. public static void main (String[]args){``` char[] fakeString = {‘m’,’c’,’g’,’k’,’s’}; for (int i = 0; i < fakeString.length; i++){ System.out.println(fakeString[i] + “ “); } // Three different ways to initialize an int[][]. //Applies to 2D arrays of another type too. int[][] multiA = new int[3][4]; // first number is the # of arrays in multiA // second number is the # of items of each array in multiA // for multiA, all arrays must be the same length. // for multiB, the arrays within can have different lengths. int[][] multiB = new int[3][];`````` multiB[0] = new int[4]; // each row, 0,1 and 2 mutliB[1] = new int[4]; // can be a different length multiB[2] = new int[4]; int[][] multiC = new int[][]{ {0,0,0,0}, // can make these different lengths as well {0,0,0,0}, {0,0,0,0}, }; // for multiC, arrays within can have different lengths. }````Lets try these 2 problems:``Write test cases. Compare with your neighbors.``1. Calculate and return how many zeros are in the parameter``(a rectangular 2D array of integers)``public static int countZeros2D(int[][] nums){```` } ````Hint for problem 2: First make a function to print a 1D array.Then make a function to print a 2d array.THEN you can attempt these problems.``2. Fill the given 2-dimensional array of integers with 1's.Where the row number is the same as the column number: you must fill those with 3's instead.`public static void fill2D(int[][] vals){  }`3. Make a new 2d array the same dimensions as the given parameter.``Fill that array with with 1's, ``except where the row number is the same as the column number:`` you must fill those with 3's instead.``You may NOT modify vals.`public static int[][] fill2DCopy(int[][] vals){  }
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