View Compilation Error

0_0_20480287_31812.cpp:7:12: error: variable or field 'merge' declared void
 void merge(a, b) {
            ^
0_0_20480287_31812.cpp:7:12: error: 'a' was not declared in this scope
0_0_20480287_31812.cpp:7:15: error: 'b' was not declared in this scope
 void merge(a, b) {
               ^
0_0_20480287_31812.cpp: In function 'int main()':
0_0_20480287_31812.cpp:33:26: error: 'merge' was not declared in this scope
    merge(find(a), find(b));
                          ^