同樣只上程式，都是簡單題

#include<iostream>
using namespace std;
int main()
{
	int in[128], count = 0;
	char n,temp[100];
	memset(in, 0, sizeof(int)* 128);
	gets(temp);
	int len = strlen(temp);
	if (len <= 0)
	{
		return 0;
	}
	for (int i = 0; i < len; i++)
	{
		in[temp[i]]++;
	}
	
	for (int i = 0; i<128; i++)
	{
		if (in[i] != 0)
		{
			count++;
		}
	}
	cout << count << endl;
	return 0;
}
 

#include<iostream>
using namespace std;
int main()
{
char in[100];
gets(in);
int len =strlen(in);
for(int i=len-1;i>=0;i--)
{
cout<<in[i];
}
cout<<endl;
}

#include<iostream>
using namespace std;
int main()
{
	char in[100], temp;
	gets_s(in);
	int len = strlen(in);
	for (int i = 0; i<len / 2; i++)
	{
		temp = in[i];
		in[i] = in[len - i - 1];
		in[len - i - 1] = temp;
	}
	cout << in << endl;
	return 0;
}
 

#includeiostream
#includevector
#includestring
using namespace std;
int main()
{
	vectorstring ss;
	string s;
	while (cin  s)
	{
		ss.push_back(s);
	}
	for (int k = ss.size()-1; k =0 ; k--)
	{
		cout  ss[k];
		if (k != 0)
		{
			cout  ' ';
		}
	}
	return 0;
}

對於最後一題是重複的前面已經寫過在此給出連結