C++ 统计一串字符各种字符的数

头文件
#include
#include
#include
#include
#include
void count(char a[]);
using namespace std;

void count(char a[])
{
int D_num=0,X_num=0,num=0,spen=0,other=0;

int i;
for(i=0;i<=(strlen(a)-1);i++)
{
    if(a[i]>='a' && a[i]<='z')
        X_num++;
    else if(a[i]>='A' && a[i]<='Z')
        D_num++;
    else if(a[i]>='0' && a[i]<='9')
        num++;
    else if(a[i]==' ')
        spen++;
    else
        other++;
}
cout<<"小写字符为："<<X_num;
cout<<"大写字母为:"<<D_num;
cout<<"数字为:"<<num;
cout<<"空格为:"<<spen;
cout<<"其他为:"<<other<<endl;

}

.CPP
#include "stdafx.h"

void main()
{
int i;
char a[1000];

cout<<"请输入一串文字:"<<endl;

for(i=0;a[i]=getchar()!='\n';i++){}

cout<<"核查如下："<<endl;

count(a);
_getch();

}
为什么运行结果 只有把其他统计 数字什么的不统计 哪里有问题

主函数里for写成这样试试：
for(i=0;(a[i]=getchar()) != '\n';i++)

 // ConsoleApplication1.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

#include <iostream>
#include <string>

using namespace std;

void count(char a[])
{
    int D_num = 0, X_num = 0, num = 0, spen = 0, other = 0;

    int i;
    for (i = 0; i <= (strlen(a) - 1); i++)
    {
        if (a[i] >= 'a' && a[i] <= 'z')
            X_num++;
        else if (a[i] >= 'A' && a[i] <= 'Z')
            D_num++;
        else if (a[i] >= '0' && a[i] <= '9')
            num++;
        else if (a[i] == ' ')
            spen++;
        else
            other++;
    }
    cout << "lowcase" << X_num;
    cout << "upcase" << D_num;
    cout << "num" << num;
    cout << "space" << spen;
    cout << "other" << other << endl;
}

int _tmain(int argc, _TCHAR* argv[])
{
    int i;
    char * a = new char[1000];
    memset(a, 0, 1000);

    cout << "please enter:" << endl;

    cin >> a;

    cout << "result as below" << endl;

    count(a);

    return 0;
}

for(i=0;(a[i]=getchar()) != '\n';i++)
这是正解。表达式结合性错误，按照lz的写法，a[i]得到的是getchar()) != '\n'这个判断的结果而不是getchar