Ever wanted to look in console at variables you use? Meet these helper functions!

dbg()

DeBuG

Suppose we have some nested containers(vector, string, bitset, set, map) or arrays, which for simplicity we may consider a multidimensional array. dbg() can neatly print the name, bounds and, at last, the values from the required sub-array with automatic bound checking:

For example:

    int j[2][2][3] = {{{4,5,6},{10,11,12}}, {{1,2,3}, {7,8,9}}};
    dbg(j);
    dbg(j, 0,0, 0,1, 0,1);
    
    output: 
    [[[4, 5, 6],
      [10, 11, 12]],
     [[1, 2, 3],
      [7, 8, 9]]]
      
    [[[4, 5],
      [10, 11]]]

    set<vector<string>> b[3] = {{{"abc", "def"},{"ghi"}}, {{"klm","nop"},{"qrs"}}, {{"tuv", "wxy", "zab"}}};
    dbg(b,1,2,0,0,0,0,1,2);
    dbg(b,1,2,0,0,0,0);
    dbg(b,1,2,0,0);
    dbg(b,1,2);
    dbg(b);
    
    output:
        
    [b,1,2,0,0,0,0,1,2]:
    [[["lm"]], [["uv"]]]

    [b,1,2,0,0,0,0]:
    [[["klm"]], [["tuv"]]]

    [b,1,2,0,0]:
    [[["klm", "nop"]], [["tuv", "wxy", "zab"]]]

    [b,1,2]:
    [[["klm", "nop"], ["qrs"]], [["tuv", "wxy", "zab"]]]

    [b]:
    [[["abc", "def"], ["ghi"]], [["klm", "nop"], ["qrs"]], [["tuv", "wxy", "zab"]]]

You pass the name of array and [two closed bounds] for each dimension(btw, you can omit several last bounds). If they are too large, dbg() reduces them. By default the bounds are set on the start and the end of each dimension.

+If you pass bounds [l;r] to the dimension that is map or set, the output goes from the lth largest to the rth largest key, or to the last element of dimension(if r is too big).

+dbg() works with c-arrays whose sizes of dimensions are constant and known at compile time.

const int N = 3, M = 2;
int main(){
    for(int i = 0; i < 4; ++i){
        char b[3][2] = {'p','q','r','s'};
        dbg(b);
    }
}

int main(){
    for(int i = 0; i < 4; ++i){
        char b[3][2] = {'p','q','r','s'};
        dbg(b);
    }
}

/*-----------------------------------------------*/

dbgm()

DeBuG Multiple

You can print the names of several variables first and values next:

    string s = {"codeforces"};
    int t = 5; char u = 'R';
    pair<pair<double, unsigned int>, pair<int, string>> v = {{234.34534, 42}, {133, "IOI"}};

    dbgm(s,t,u,v);
    
    output:
        
    [s,t,u,v]: "codeforces" | 5 | R | ((234.345340, 42), (133, "IOI")) |

/*-----------------------------------------------*/


Here's my code. It's hugely inspired by this submission by tourist.

The compact version is created from the extended one by means of http://removelinebreaks.net/.


/*-----------------------------------------------*/

Hope these functions save your precious minutes during contests. Enjoy!

P.S. Optionally, you can add this line for printing arbitrary number of variables with cout

void dbgs(){;} template<typename Heads, typename... Tails> void dbgs(Heads H, Tails... T){ cout << H << " "; dbgs(T...); }
 

Thanks to this post by HosseinYousefi

UPD: dbgm() added