0_0_15692387_14504.cpp:3:11: error: '::main' must return 'int' void main() ^ 0_0_15692387_14504.cpp: In function 'int main()': 0_0_15692387_14504.cpp:7:9: error: unable to find string literal operator 'operator""a' printf("%d+%d"a,b); ^