View Compilation Error

0_0_31046076_4324.cpp: In function 'int main()':
0_0_31046076_4324.cpp:5:25: error: 'scanf' was not declared in this scope
     while(scanf("%d", &n) != EOF)
                         ^
0_0_31046076_4324.cpp:5:30: error: 'EOF' was not declared in this scope
     while(scanf("%d", &n) != EOF)
                              ^
0_0_31046076_4324.cpp:16:28: error: 'abs' was not declared in this scope
                 if(abs(a[j]) < abs(a[j+1]))
                            ^
0_0_31046076_4324.cpp:27:46: error: 'printf' was not declared in this scope
             if(i == n-1) {printf("%d\n", a[i]); break;}
                                              ^
0_0_31046076_4324.cpp:28:31: error: 'printf' was not declared in this scope
             printf("%d ", a[i]);
                               ^