View Compilation Error

0_0_38396681_12977.cpp: In function 'int main()':
0_0_38396681_12977.cpp:11:25: error: 'printf' was not declared in this scope
  printf("输入两点的坐标");
                         ^
0_0_38396681_12977.cpp:15:58: error: 'scanf' was not declared in this scope
  while (scanf("%f%f%f%f%c", &p1.x, &p1.y, &p2.x, &p2.y, a) != EOF) {
                                                          ^
0_0_38396681_12977.cpp:15:63: error: 'EOF' was not declared in this scope
  while (scanf("%f%f%f%f%c", &p1.x, &p1.y, &p2.x, &p2.y, a) != EOF) {
                                                               ^