View Compilation Error

0_0_32332091_348.cpp: In function 'int main()':
0_0_32332091_348.cpp:5:40: error: 'scanf' was not declared in this scope
     while (scanf("%d%d%d", &a, &v1, &v2) == 3) {
                                        ^
0_0_32332091_348.cpp:6:29: error: 'puts' was not declared in this scope
         if (a == 0) puts("0");
                             ^
0_0_32332091_348.cpp:7:43: error: 'puts' was not declared in this scope
         else if (v1 <= v2) puts("Infinity");
                                           ^
0_0_32332091_348.cpp:8:65: error: 'printf' was not declared in this scope
         else printf("%.4f\n", 1.0 * a * v1 / (v1 * v1 - v2 * v2));
                                                                 ^