Testcase Input Formatting Validator Template

input_testfile_formatting_validator_template.cpp

// Original file - https://pastebin.com/Vk8tczPu
#include <iostream>
#include <assert.h>
#include <algorithm>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <map>
using namespace std;
  
  
long long readInt(long long l,long long r,char endd){
	long long x=0;
	int cnt=0;
	int fi=-1;
	bool is_neg=false;
	while(true){
		char g=getchar();
		if(g=='-'){
			assert(fi==-1);
			is_neg=true;
			continue;
		}
		if('0'<=g && g<='9'){
			x*=10;
			x+=g-'0';
			if(cnt==0){
				fi=g-'0';
			}
			cnt++;
			assert(fi!=0 || cnt==1);
			assert(fi!=0 || is_neg==false);
			
			assert(!(cnt>19 || ( cnt==19 && fi>1) ));
		} else if(g==endd){
			if(is_neg){
				x= -x;
			}
			assert(l<=x && x<=r);
			return x;
		} else {
			assert(false);
		}
	}
}
string readString(int l,int r,char endd){
	string ret="";
	int cnt=0;
	while(true){
		char g=getchar();
		assert(g!=-1);
		if(g==endd){
			break;
		}
		cnt++;
		ret+=g;
	}
	assert(l<=cnt && cnt<=r);
	return ret;
}
long long readIntSp(long long l,long long r){
	return readInt(l,r,' ');
}
long long readIntLn(long long l,long long r){
	return readInt(l,r,'\n');
}
string readStringLn(int l,int r){
	return readString(l,r,'\n');
}
string readStringSp(int l,int r){
	return readString(l,r,' ');
}
  
int main()
{
	int T=readIntLn(1,3); // Ensures that an integer in the range [1, 3] is inputted, and that there is a New Line (Ln) right after that. This needs Unix-style line endings (ie. \n instead of \r\n). So generate the test files on an Unix machine (eg. Linux, Mac).

	while(T--)
	{
	  
	  int n=readIntSp(1,1000000); // Ensures that an integer in the range [1, 1000000] is inputted, and that there is a space (Sp) right after that.
	  int m=readIntSp(0,1000000);
	  int k=readIntLn(1,1000000);
	  
	  for(int i=1;i<=m;i++)
	  {
		int u=readIntSp(1, n);
		int v=readIntLn(1, n);
	  }
	
	}    
		
	assert(getchar()==-1); // Ensures that there are no extra characters at the end.
	cerr<<"SUCCESS\n"; // You should see this on the http://campus.codechef.com/files/stderr/SUBMISSION_ID page, at the bottom.
}

How is this useful, can you explain it a bit please?

Hey @D-Aman-S,
This test file validation template can be used to verify if your test cases are well-written and formatted correctly as per the constraints of your question, It can be used to check things like if the numbers are within the defined range, if the whitespace and linebreaks are correct, etc.