C++求助为何空格不管用？

#include<bits/stdc++.h>
using namespace std;

int main()
{
	char st;
	int i=0;
	while(cin>>st)
	{
		if(st==' ')i++;
		else if(st=='a')i++;
		else if(st=='b')i+=2;
		else if(st=='c')i+=3;
		else if(st=='d')i++;
		else if(st=='e')i+=2;
		else if(st=='f')i+=3;
		else if(st=='g')i++;
		else if(st=='h')i+=2;
		else if(st=='i')i+=3;
		else if(st=='j')i++;
		else if(st=='k')i+=2;
		else if(st=='l')i+=3;
		else if(st=='m')i++;
		else if(st=='n')i+=2;
		else if(st=='o')i+=3;
		else if(st=='p')i++;
		else if(st=='q')i+=2;
		else if(st=='r')i+=3;
		else if(st=='s')i+=4;
		else if(st=='t')i++;
		else if(st=='u')i+=2;
		else if(st=='v')i+=3;
		else if(st=='w')i++;
		else if(st=='x')i+=2;
		else if(st=='y')i+=3;
		else if(st=='z')i+=4;
	 
	}
	cout<<i;
    return 0;
}