View Compilation Error

0_0_18772492_18784.cpp: In function 'int main(int, char**)':
0_0_18772492_18784.cpp:7:5: error: 'num' was not declared in this scope
     num=1;
     ^
0_0_18772492_18784.cpp:8:13: error: 'str' was not declared in this scope
  scanf("%s",str);
             ^
0_0_18772492_18784.cpp:9:6: error: 'i' was not declared in this scope
  for(i=0;i<strlen(str);i++)
      ^
0_0_18772492_18784.cpp:13:2: error: 'else' without a previous 'if'
  else
  ^
0_0_18772492_18784.cpp:17:20: error: 'i' was not declared in this scope
    printf("%c",str[i]);
                    ^
0_0_18772492_18784.cpp:22:27: error: 'i' was not declared in this scope
    printf("%d %c",num,str[i]);
                           ^