View Compilation Error

0_0_27641070_28261.cpp:3:11: error: '::main' must return 'int'
 void main()
           ^
0_0_27641070_28261.cpp: In function 'int main()':
0_0_27641070_28261.cpp:16:5: error: 'k' was not declared in this scope
 for(k=1;k<key[1];k++)
     ^