foo.cpp: In function 'int main()':
foo.cpp:20:16: error: 'scanf' was not declared in this scope
foo.cpp:36:50: error: 'printf' was not declared in this scope
foo.cpp:37:22: error: 'printf' was not declared in this scope
foo.cpp:19:8: warning: unused variable 'j' [-Wunused-variable]