how to use stl::map as two dimension array

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感动是毒 2020-12-16 07:09

Could you let us know how to use stl:map as two dimension array? I wanted to access the individual elements as like mymap[i][j] where I do not know beforehand what the value

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陌清茗 (楼主)

2020-12-16 07:30

You can do

std::map > mymap;

For example:

#include 
#include 

int main() 
{
    std::map > mymap;

    mymap[9][2] = 7;
    std::cout << mymap[9][2] << std::endl;

    if (mymap.find(9) != mymap.end() && mymap[9].find(2) != mymap[9].end()) {
        std::cout << "My map contains a value for [9][2]" << std::endl;
    } else {
        std::cout << "My map does not contain a value for [9][2]" << std::endl;
    }

    return 0;
}

prints 7 on the standard output, followed by "My map contains a value for [9][2]".

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