View Compilation Error

0_0_25071835_9364.cpp:2:2: error: 'usingnamespace' does not name a type
  usingnamespace std; 
  ^
0_0_25071835_9364.cpp: In function 'int main()':
0_0_25071835_9364.cpp:25:2: error: 'return0' was not declared in this scope
  return0;
  ^