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Have you compared it with this template for debugging which is also based on a submission by tourist? If yes, then how does it compare?

Does not work for vector :( And of course for arrays

amazing, i just learn c++ template, and then i find these good stuffs.

.

Doesn't work with arrays. How can I modify it to work with arrays?

The same thing can be achieved by overloading ostream for STL containers (this way nested structures work too). Also, you can come up with some pretty neat one liners using fold expressions and lambdas.

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

#define tr(...) pr("(", __LINE__, ")[", #__VA_ARGS__, "]: ["), pc(__VA_ARGS__)

template<class T1, class T2> istream& operator>>(istream& is, pair<T1,T2>& p) { is >> p.first >> p.second; return is; }
template<class T> istream& operator>>(istream& is, vector<T>& v) { for(auto& x: v) is >> x; return is; }
auto re = [](auto&&... args) { (cin >> ... >> args); };

template<class T1, class T2> ostream& operator<<(ostream& os, pair<T1,T2> p) 
{ os << "(" << p.first << ", " << p.second << ")"; return os; }

#define Vout(Con) template<class T> ostream& operator<<(ostream& os, Con<T>& v) { bool fst = 1; os << "{"; \
for(auto& x: v) { if(!fst) os << ", "; os << x; fst = 0; } os << "}"; return os; }
#define Vout2(Con) template<class T1, class T2> ostream& operator<<(ostream& os, Con<T1,T2>& v) { bool fst = 1; os << "{"; \
for(auto& [x, y]: v) { if(!fst) os << ", "; os << x << ": " << y; fst = 0; } os << "}"; return os; }
Vout(vector) Vout(set) Vout(multiset) Vout2(map)

#define Out(f, delim, lst) auto f = [](auto&& arg, auto&&... args) { cout << arg; ((cout << delim << args), ...); cout << lst; };
Out(pr, "", "") Out(pw, ' ', ' ') Out(ps, ' ', '\n';) Out(pc, ", ", "]" << '\n';)

auto ptrace = [](const char* name, auto&& A, auto&&... rest) {
    const char* open = strchr(name, '['); cout.write(name, open-name);
    ((cout << '[' << rest << ']'), ...); cout << " = " << A << '\n';;
};

int32_t main() {
    int a = 3; char c = 'z';
    string s = "asdf";
    vector<vector<pair<int, int>>> v{
        {{1, 2}, {2, 3}, {3, 4}}, 
        {{-1, 23}}, 
        {}, 
        {{42, 42}, {-1, -3}}
    };
    tr(a, c, s);
    tr(v);
}

(36)[a, c, s]: [3, z, asdf]
(37)[v]: [{{(1, 2), (2, 3), (3, 4)}, {(-1, 23)}, {}, {(42, 42), (-1, -3)}}]

If you'd like a more generic reader-writer/debugger template (using SFINAE) for C++ STL, you can look at submissions by @Narut on CF.

This is super helpful Thanks! But can you tell me how to redirect the cerr output to a file.. I do it with the command freopen("error.txt", "w", stdout ) but for multiple variables, it's showing the output on the terminal

This is my template and debug will work for any complex structure.

#include <bits/stdc++.h>
using namespace std;
/******** Debug Code *******/
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename A>
void __print(const A &x);
template <typename A, typename B>
void __print(const pair<A, B> &p);
template <typename... A>
void __print(const tuple<A...> &t);
template <typename T>
void __print(stack<T> s);
template <typename T>
void __print(queue<T> q);
template <typename T, typename... U>
void __print(priority_queue<T, U...> q);
template <typename A>
void __print(const A &x) {
    bool first = true;
    cerr << '{';
    for (const auto &i : x) {
        cerr << (first ? "" : ","), __print(i);
        first = false;
    }
    cerr << '}';
}
template <typename A, typename B>
void __print(const pair<A, B> &p) {
    cerr << '(';
    __print(p.first);
    cerr << ',';
    __print(p.second);
    cerr << ')';
}
template <typename... A>
void __print(const tuple<A...> &t) {
    bool first = true;
    cerr << '(';
    apply([&first](const auto &...args) { ((cerr << (first ? "" : ","), __print(args), first = false), ...); }, t);
    cerr << ')';
}
template <typename T>
void __print(stack<T> s) {
    vector<T> debugVector;
    while (!s.empty()) {
        T t = s.top();
        debugVector.push_back(t);
        s.pop();
    }
    reverse(debugVector.begin(), debugVector.end());
    __print(debugVector);
}
template <typename T>
void __print(queue<T> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.front();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}
template <typename T, typename... U>
void __print(priority_queue<T, U...> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.top();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}
void _print() { cerr << "]\n"; }
template <typename Head, typename... Tail>
void _print(const Head &H, const Tail &...T) {
    __print(H);
    if (sizeof...(T))
        cerr << ", ";
    _print(T...);
}
#ifndef ONLINE_JUDGE
#define debug(...) cerr << "Line:" << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; _print(__VA_ARGS__)
#else
#define debug(...)
#endif

I see you're using a different template these days, is your current one doing the same work as this blog but with less code?