View Compilation Error

0_0_23601660_8556.cpp: In function 'int main()':
0_0_23601660_8556.cpp:29:29: error: 'scanf' was not declared in this scope
     while(scanf("%d%d",&n,&m)!=EOF&&n!=-1)
                             ^
0_0_23601660_8556.cpp:29:32: error: 'EOF' was not declared in this scope
     while(scanf("%d%d",&n,&m)!=EOF&&n!=-1)
                                ^
0_0_23601660_8556.cpp:31:29: error: 'memset' was not declared in this scope
         memset(g,0,sizeof(g));
                             ^
0_0_23601660_8556.cpp:36:23: error: 'strlen' was not declared in this scope
             x=strlen(s);
                       ^
0_0_23601660_8556.cpp:43:26: error: 'printf' was not declared in this scope
         printf("%d\n",sum);
                          ^