Help me in solving GSCV211 problem

My issue

why we using t-- in while loop condition

My code

// Write out the syntax in the blanks below

#include <bits/stdc++.h>
using namespace std;

int main() 
 int t;
 //accept the count of test cases given in the the 1st line
 //Run a loop to accept 't' inputs
   int A,B;
   string S;
 //accept 2 integers on the 1st line of each test case
 //accept 1 string on the 2nd line of each test case
 //output the 5 integers on a single line for each test case 
   cout<<A<<" "<<B<<" "<<S<<endl;
 return 0;

Learning course: C++ for problem solving - 1
Problem Link: CodeChef: Practical coding for everyone