CF 5B Center Alignment

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
using namespace std;
const int MAX = 1005;

char data[MAX][MAX];
int data_len[MAX];
int main()
{
int num = 0,max_len = 0;
while(gets(data[num]))
{
data_len[num] = strlen(data[num]);
if(max_len < data_len[num])
max_len = data_len[num];
num++;
}
for(int i = 0;i <= max_len + 1;i ++)
printf("*");
printf("\n");
int flag = 0;
for(int i = 0;i < num;i ++)
{
printf("*");
if(data_len[i] < max_len)
{
if((max_len-data_len[i])%2==0)///even num
{
for(int j = 1;j <=(max_len-data_len[i])/2;j ++)
printf(" ");
printf("%s",data[i]);
for(int j = 1;j <=(max_len-data_len[i])/2;j ++)
printf(" ");
}
else
{
if(flag == 0)
{
for(int j = 1;j <= (max_len-data_len[i])/2;j ++)
printf(" ");
printf("%s",data[i]);
for(int j = 1;j <=(max_len-data_len[i])/2 + 1; j ++)
printf(" ");
flag =1;
}
else if(flag)
{
for(int j = 1;j <= (max_len-data_len[i])/2+1;j ++)
printf(" ");
printf("%s",data[i]);
for(int j = 1;j <=(max_len-data_len[i])/2;j ++)
printf(" ");
flag =0;
}
}
}
else
printf("%s",data[i]);
printf("*\n");
}
for(int i = 0;i <= max_len + 1;i ++)
printf("*");
printf("\n");
return 0;
}