View Compilation Error

0_0_13077729_388.cpp: In function 'int main()':
0_0_13077729_388.cpp:5:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&t)!=EOF)
                        ^
0_0_13077729_388.cpp:5:27: error: 'EOF' was not declared in this scope
     while(scanf("%d",&t)!=EOF)
                           ^
0_0_13077729_388.cpp:11:28: error: 'strlen' was not declared in this scope
             len=strlen(line);
                            ^
0_0_13077729_388.cpp:17:28: error: 'printf' was not declared in this scope
             printf("%d\n",s);
                            ^