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Following method is a part of a class MyArray. int check(int m[ ], int i) { if (i <= 0) { return 0…

Computer Science20252 marksShort answer
Following method is a part of a class MyArray.
int check(int m[ ], int i) 
{ 
    if (i <= 0)  
    { 
        return 0; 
    } 
    return check(m, i - 2) + m[i - 1]; 
} 

public static void main( ) 
{ 
    int m[ ] = {1, 2, 3, 4}; 
    int ans = check(m, m.length); 
    System.out.println(ans); 
}
(a)[1.0]
Predict the output of the code considering there is no compilation error. Show the working.
(b)[1.0]
Considering the if condition is changed to `if(i < 0)`, how will it affect the output?

Answer

Answer (a)

AI
Output: 6 Working: check(m,4) = check(m,2) + m[3] = check(m,2) + 4 check(m,2) = check(m,0) + m[1] = check(m,0) + 2 check(m,0): since i=0 <= 0, returns 0 So check(m,2) = 0 + 2 = 2, and check(m,4) = 2 + 4 = 6. ans = 6

Answer (b)

AI
With if(i < 0), the base case i=0 is no longer true (0 is not < 0), so recursion does not stop there: check(m,0) calls check(m,-2) + m[-1], and m[-1] is an invalid array index. The program throws an ArrayIndexOutOfBoundsException (index -1) instead of returning a value, so it crashes rather than printing 6.
Recursion

From ISC Computer Science - Competency Focused Practice Questions (CISCE, August 2024), question 56.

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