Sequential search, half search, block search~

In order to find

int Search(int a[],int n,int key){
    
	for(int i=0;i<n;i++)
		if(a[i]==key)
			return i;
	return 0;
}

Binary search ( The linear table is required to be orderly ,eg： Increasing , Decline )

int Bsearch(int a[],int low,int high,int key){
    
	int mid;
	while(low<=high){
    
		mid=(low+high)/2;
		if(a[mid]==key)
			return mid;
		else if(a[mid]>key)
			high=mid-1;
		else
			low=mid+1;	
	}
}

Search in blocks

// Index table definition 
typedef struct{
    
	int key;                 // Assume that the elements in the table are  int  type 
	int low,high;            // Record the subscript of the first element and the last element in a block 
}indexElem;
indexElem index[maxSize];    // Define index table