View Compilation Error

0_0_38363906_18846.cpp: In function 'int main()':
0_0_38363906_18846.cpp:11:19: error: 'strupr' was not declared in this scope
        strupr(strr);
                   ^
0_0_38363906_18846.cpp:12:22: error: 'strlen' was not declared in this scope
   int len=strlen(strr),num=0;
                      ^
0_0_38363906_18846.cpp:16:4: error: 'num' was not declared in this scope
    num++;
    ^
0_0_38363906_18846.cpp:18:19: error: 'num' was not declared in this scope
   printf("%.5f\n",num*1.0/len*1.0);
                   ^