C++中關(guān)于delete的一個小問題

C++函數(shù)（非主函數(shù)）里面定義的一個指針，在函數(shù)末尾需要自己手動delete么？還是系統(tǒng)會自動delete？
如這段代碼的最后，那個delete是否多余？

void mergeArray(int * & A, int low, int high)
{
    int cnt = 0;
    int * B = new int[high - low + 1];
    int mid = low + (high - low) / 2;
    int i = low;
    int j = mid + 1;
    while( mid + 1 > i && high + 1 > j ) {
        if ( A[i] < A[j] )    B[cnt++] = A[i++];
        else    B[cnt++] = A[j++];
    }
    while( mid + 1 > i )    B[cnt++] = A[i++];
    while( high + 1 > j )    B[cnt++] = A[j++];
//    A:loop from low, B:loop from 0 
    for ( i = low, cnt = 0; i < high + 1; i++ )    A[i] = B[cnt++];
    delete[] B;
}