View Compilation Error

0_0_23793649_10335.cpp: In function 'void ShellSort(std::vector<int>&)':
0_0_23793649_10335.cpp:25:51: error: 'tmp' was not declared in this scope
                 for(k = j - gap; k >= i && v[k] > tmp; k -= gap) {
                                                   ^
0_0_23793649_10335.cpp:28:30: error: 'tmp' was not declared in this scope
                 v[k + gap] = tmp;
                              ^