二分法搜索某个数

二分法搜索某个数（有序序列中）

static int binarySearch(int[] a,int value){
    int left=0;
    int right=a.length-1;
    while(left<=right){
    int middle = left+((right-left)>>1);
    if(a[middle]>value){
    right=middle+1;

}else if{
    left=middle+1;
}else{
return middle;
}
}
return -1;
}