C :

#include<stdio.h>
int main()
{
	char str[101][21];
	int n,i,j;
	scanf("%d\n",&n);
	for(i=0;i<n;i++)
	{
		gets(str[i]);
		for(j=1;j<=i+1;j++)
		{
			printf("%d=%s",j,str[i-j+1]);
			if(j!=i+1&&j!=4)
				printf(" ");
			if(j==4)
				break;
		}
		printf("\n");
	}
	return 0;
}

C++ :

#include <cstdio>
#include <vector>
#include <string>
#include <iostream>
using namespace std;

int main() {
    //freopen("data.in", "r", stdin);
    //freopen("data.out", "w", stdout);
    int t;
    vector < string > vs;
    string s;
    cin >> t;
    while (t--) {
        cin >> s;
        vs.push_back(s);
        if (vs.size() > 4)
            vs.erase(vs.begin());
        int cnt = 1;
        for (vector < string >::reverse_iterator it = vs.rbegin(); it != vs.rend(); ++it, ++cnt) {
            if (1 != cnt) cout << " ";
            cout << cnt << "=" << *it;
        }
        cout << endl;
    }
    return 0;
}