View Compilation Error

0_0_25795776_23606.cpp: In function 'int main()':
0_0_25795776_23606.cpp:14:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&n)!=EOF)
                        ^
0_0_25795776_23606.cpp:14:27: error: 'EOF' was not declared in this scope
     while(scanf("%d",&n)!=EOF)
                           ^
0_0_25795776_23606.cpp:22:31: error: 'memset' was not declared in this scope
         memset(c1,0,sizeof(c2));
                               ^
0_0_25795776_23606.cpp:31:30: error: 'abs' was not declared in this scope
                 c2[abs(j-w[i])]+=c1[j];
                              ^
0_0_25795776_23606.cpp:46:26: error: 'printf' was not declared in this scope
         printf("%d\n",cnt);
                          ^