src.cpp: In function 'int main()':
src.cpp:10:27: error: 'stdin' was not declared in this scope
freopen("SUM.INP","r",stdin);
^
src.cpp:10:32: error: 'freopen' was not declared in this scope
freopen("SUM.INP","r",stdin);
^
src.cpp:11:27: error: 'stdout' was not declared in this scope
freopen("SUM.OUT","w",stdout);
^