Practice Test GeeksAP CSA - Advanced Placement Computer Science A Practice Test
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String Manipulation and 2D Arrays Flashcards

6 cards from real AP CSA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. What does `String.valueOf(42)` return?

    Answer: "42"

    String.valueOf(int) converts the integer 42 to its String representation "42".

  2. What is the purpose of `str.trim()` in Java?

    Answer: Returns a new String with leading and trailing whitespace removed

    trim() returns a copy of the String with whitespace (spaces, tabs, newlines) stripped from both the beginning and end.

  3. What is the sum of all elements in a 2D array `int[][] a = {{1,2},{3,4},{5,6}}`?

    Answer: 21

    Summing all elements: 1+2+3+4+5+6 = 21, using a nested loop to add each element.

  4. What does `str.contains("ell")` return for `str = "Hello"`?

    Answer: true

    contains() returns true if the specified sequence appears anywhere within the String; "ell" is found within "Hello".

  5. What keyword makes a String variable refer to a string literal shared in the string pool?

    Answer: No special keyword — string literals are automatically pooled

    Java automatically places String literals in the string pool; no keyword is needed, though intern() can force pool placement for non-literal strings.

  6. In a 2D array, what does `matrix[0].length` represent?

    Answer: The number of columns in row 0

    matrix[0] refers to the first row (itself an array), and .length on that row gives the number of columns.