How do i change the format of I/O? - c

Question

Input format: The first line of input gives the number the input strings (without spaces and of maximum 100 length
and in lowercase). Then there is following n lines, each containing a string.
Output format: N lines of output, each line has either YES or NO following by newline. (YES if string is a magic square palindrome otherwise NO)
Sample Input:
4
satorarepotenetoperarotas
aba
abba
abcabacba
Sample Output:
YES
NO
YES
NO
So i have written the following code.But in my program the output gets displayed immediately after the input and it takes only one input at a time.
PS:If you have any suggestions on how to make the code more efficient,please add them in your answer.Thanks
#include<stdio.h>
#include<math.h>
#include<string.h>
int main()
{ int num_input,l;
scanf("%d",&num_input);
for(l=0;l<num_input;l++)
{
char str[100];
char i = 0;
int sq,j,k;
scanf("%s", str);
while(str[i]!='\0')
{
++i;
}
sq = sqrt(i);
if(i== sq*sq)
{
if(i%2==0)
{
for(j=0;j<=i/2;j++)
{
if((str[j]==str[i-j-1])&&(str[j+sq]==str[i-j-sq-1]))
{
if(j==i/2)
{
printf("YES\n");
}
}
else
{ if(j==i/2)
{
printf("NO\n");
}
}
}
}
if(i%2!=0)
{
for(k=0;k<=i/2;k++)
{
if((str[k]==str[i-k-1])&&(str[k+sq]==str[i-k-sq-1]))
{ if(k==i/2)
{
printf("YES\n");
}}
else
{if(j==i/2)
{
printf("NO\n");
}}
}
}
}
else
{
printf("NO\n");
}
}
return 0;
}

Answer 1

The problem of 'mixed' output and input is caused by the fact, that you take one string per calculation. If you want to scan the whole input, then display the output, you should... do exactly that. Simple approach how to do it, given that you know how many strings will be typed:
After you scan the number of strings with int num_input; scanf("%d",&num_input);, you can create a two-dimensional array of characters sized as [num_input][max_str_length]. From your code, I assume that maximal length of each individual string is 100 (given char str[100];).
Then, in a for loop, that loops num_input times, you should scan all your strings and place them in the proper places in your 2D array. This way, your input is stored and ready to be checked by an algorithm. I would encourage you to, instead of writing plain algorith inside of main function, create a function that will take an array and it's size as arguments and return true or 1 when given array contains a string that is a "magic square palindrome" or return false / 0 when it's not. If you do that, you can just loop num_input times again and call your function on currently checked array. Each time the fucntion returns true, you output "YES", otherwise "NO"/
If you don't know anything about 2D arrays and/or making functions yourself, I encourage you to either buy a good C book, or simple google some tutorials, because that stuff is pretty basic and fairly easy to understand.