View Compilation Error

0_0_4785342_20937.cpp: In function `int& sum(elemtype, elemtype)':
0_0_4785342_20937.cpp:6: error: invalid initialization of non-const reference of type 'int&' from a temporary of type 'int'
0_0_4785342_20937.cpp: At global scope:
0_0_4785342_20937.cpp:9: error: `main' must return `int'