foo.cc: In function 'double f(double)':
foo.cc:19:14: warning: decomposition declaration only available with -std=c++1z or -std=gnu++1z
     for (auto[left, right, m, b]: lines){
              ^
foo.cc:24:14: warning: decomposition declaration only available with -std=c++1z or -std=gnu++1z
     for (auto[a, r]:disks){
              ^
foo.cc: In function 'int main()':
foo.cc:79:14: warning: decomposition declaration only available with -std=c++1z or -std=gnu++1z
     for (auto[a,r]:disks){
              ^

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