Write the following Java methods and test them from the main () method. Write a

Question

Write the following Java methods and test them from the main () method.

Write a Java method to find the largest, smallest and the closest (to the middle range in between) number from a given integer array. The integer array is received as a parameter.

Write a method to find a given number from a given sorted integer array. The array and the number to search for are received as parameters.

Write a method to find a given number from a given non sorted integer array. The array and the number to search for are received as parameters.

Develop a method to count the number of vowels in a given array of strings. The array is received as a parameter.

Write a Java method to multiply two N × N matrices (2D arrays). The two matrices are received as parameters. The result should be returned from the method.

Write a Java method to determine and display the sum of all the values in the primary and secondary diagonals of a 2D integer array. The 2D integer array is received as a parameter to the method. An example is shown below.

Explanation / Answer

1

#include<stdio.h>

int maxDiff(int arr[], int arr_size)
{   
int max_diff = arr[1] - arr[0];
int i, j;
for(i = 0; i < arr_size; i++)
{
for(j = i+1; j < arr_size; j++)
{
if(arr[j] - arr[i] > max_diff)   
max_diff = arr[j] - arr[i];
}
}
return max_diff;
}

int main()
{
int arr[] = {1, 2, 90, 10, 110};
printf("Maximum difference is %d", maxDiff(arr, 5));
getchar();
return 0;
}

2

/* if x is present in arr[] then returns the count of occurrences of x,
otherwise returns -1. */
int count(int arr[], int x, int n)
{
int i; // index of first occurrence of x in arr[0..n-1]
int j; // index of last occurrence of x in arr[0..n-1]

/* get the index of first occurrence of x */
i = first(arr, 0, n-1, x, n);

/* If x doesn't exist in arr[] then return -1 */
if(i == -1)
return i;
  
/* Else get the index of last occurrence of x. Note that we
are only looking in the subarray after first occurrence */
j = last(arr, i, n-1, x, n);   
  
/* return count */
return j-i+1;
}

/* if x is present in arr[] then returns the index of FIRST occurrence
of x in arr[0..n-1], otherwise returns -1 */
int first(int arr[], int low, int high, int x, int n)
{
if(high >= low)
{
int mid = (low + high)/2; /*low + (high - low)/2;*/
if( ( mid == 0 || x > arr[mid-1]) && arr[mid] == x)
return mid;
else if(x > arr[mid])
return first(arr, (mid + 1), high, x, n);
else
return first(arr, low, (mid -1), x, n);
}
return -1;
}

of x in arr[0..n-1], otherwise returns -1 */
int last(int arr[], int low, int high, int x, int n)
{
if(high >= low)
{
int mid = (low + high)/2; /*low + (high - low)/2;*/
if( ( mid == n-1 || x < arr[mid+1]) && arr[mid] == x )
return mid;
else if(x < arr[mid])
return last(arr, low, (mid -1), x, n);
else
return last(arr, (mid + 1), high, x, n);
}
return -1;
}

int main()
{
int arr[] = {1, 2, 2, 3, 3, 3, 3};
int x = 3; // Element to be counted in arr[]
int n = sizeof(arr)/sizeof(arr[0]);
int c = count(arr, x, n);
printf(" %d occurs %d times ", x, c);
getchar();
return 0;
}

3

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