What is the role of while t-- here please explain

[amnkhxn]

My issue

My code

// Update the '_' in the code below

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

int main() 
{
 int t;
 //accept the count of test cases given in the the 1st line
 cin>>t;
 //Run a loop to accept 't' inputs
while(t--)
 { 
   int N;
 //accept an integer N in each test case
   _____N;
 //output the number mirror for each test case
   _____N;
  }  
 return 0;
}

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

[jasmeet16]

it is for the number of inputs…if 4 inputs are to be given so the while loop will run for 4 times…t refers to the number of inputs or you can say test cases

[amnkhxn]

Yeah ik that but what’s that – sign and how does it function there like it’s for decrease 1 I think so how does the loop will work ?

[jasmeet16]

yess t will decrement by 1 everytime and when t becomes 0 the condition for while becomes false and you exit the loop

[amnkhxn]

I understand thank you but I’ll better use for loop insted of getting confused here

[justani]

Help me in solving GSCV209 problem

TLDR: This is the shortest way to loop through all the test cases. Basically we want to loop from 1 till t so that we can handle each test. To do that we can either write a for loop like this for (int i = 1; i <= t; i++) { } But for loop needs this much code, so we use while loop. With while loop you can write a condition like while (t>0) { // Do stuff t = t-1; } We can then compress it more by just using while(t--) which will stop when t becomes zero.

[amnkhxn]

Perfect , thanks .