Input testfile formatting - Validator template

// Constraints + Formatting Validator

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

// -------------------- Input Checker Start --------------------

// This function reads a long long, character by character, and returns it as a whole long long. It makes sure that it lies in the range [l, r], and the character after the long long is endd. l and r should be in [-1e18, 1e18].
long long readInt(long long l, long long r, char endd)
{
    long long x = 0;
    int cnt = 0, fi = -1;
    bool is_neg = false;
    while(true)
    {
        char g = getchar();
        if(g == '-')
        {
            if(!(fi == -1))
                cerr << "- in between integer\n";
            assert(fi == -1);
            is_neg = true; // It's a negative integer
            continue;
        }
        if('0' <= g && g <= '9')
        {
            x *= 10;
            x += g - '0';
            if(cnt == 0)
                fi = g - '0'; // fi is the first digit
            cnt++;

            // There shouldn't be leading zeroes. eg. "02" is not valid and assert will fail here.
            if(!(fi != 0 || cnt == 1))
                cerr << "Leading zeroes found\n";
            assert(fi != 0 || cnt == 1);

            // "-0" is invalid
            if(!(fi != 0 || is_neg == false))
                cerr << "-0 found\n";
            assert(fi != 0 || is_neg == false);

            // The maximum number of digits should be 19, and if it is 19 digits long, then the first digit should be a '1'.
            if(!(!(cnt > 19 || (cnt == 19 && fi > 1))))
                cerr << "Value greater than 1e18 found\n";
            assert(!(cnt > 19 || (cnt == 19 && fi > 1)));
        }
        else if(g == endd)
        {
            if(is_neg)
                x = -x;
            if(!(l <= x && x <= r))
            {
                // We've reached the end, but the long long isn't in the right range.
                cerr << "Constraint violated: Lower Bound = " << l << " Upper Bound = " << r << " Violating Value = " << x << '\n';
                assert(false);
            }
            return x;
        }
        else if((g == ' ') && (endd == '\n'))
        {
            cerr << "Extra space found. It should instead have been a new line.\n";
            assert(false);
        }
        else if((g == '\n') && (endd == ' '))
        {
            cerr << "A new line found where it should have been a space.\n";
            assert(false);
        }
        else
        {
            cerr << "Something weird has happened.\n";
            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;
    }
    if(!(l <= cnt && cnt <= r))
        cerr << "String length not within constraints\n";
    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, ' '); }
void readEOF()
{
    char g = getchar();
    if(g != EOF)
    {
        if(g == ' ')
            cerr << "Extra space found where the file shold have ended\n";
        if(g == '\n')
            cerr << "Extra newline found where the file shold have ended\n";
        else
            cerr << "File didn't end where expected\n";
    }
    assert(g == EOF);
}

vector<int> readVectorInt(int n, long long l, long long r)
{
    vector<int> a(n);
    for(int i = 0; i < n - 1; i++)
        a[i] = readIntSp(l, r);
    a[n - 1] = readIntLn(l, r);
    return a;
}

// -------------------- Input Checker End --------------------

int main(){
    ios::sync_with_stdio(false);cin.tie(0);

// CODE TO BE MODIFIED

    int t, x;
    t=readIntLn(1,100); // This reads an integer whose value is 1 <= t <= 100, and the line should end right after this integer.
    while(t--)
    {
        x=readIntLn(1,1000); // This reads an integer whose value is 1 <= x <= 1000, and the line should end right after this integer.
    }
    readEOF(); // This ensures that there is nothing more to read in the input file.
}