There are two ways that come to mind.

One is to put the numbers in an array then call
Arrays.sort on this array. The element at offset 0
(the first elemnt in the array will be the smallest.

The other is to loop through all the numbers holding
the current smallest number in a temporary variable.
If the current number is smaller than the temporary
assign its valule to the temporary variable.

The code for both are quite simple  so I will not post
it here but asy so if you need it and I'm sure
somebody on this list(including myself) can give you
the code.

use the Math class for finding out the min,
pass a List of numbers to the userdefined function,
recursively call the function.

int minIndex(int v[], int first, int last){
if(first==last){return first;}
int tempA = min(v,first,(first+last)/2);
int tempB = min(v,(first+last)/2,last);
if(tempA<tempB) return tempA;
else return tempB;
}

need to compare the ints in the array, not the indexes.
Should be:
int minIndex(int v[], int first, int last){
if(first==last){return first;}
int tempA = min(v,first,(first+last)/2);
int tempB = min(v,(first+last)/2,last);
if(v[tempA]<v[tempB]) return tempA;
else return tempB;