View Compilation Error

0_0_35812416_6778.cpp:4:11: error: '::main' must return 'int'
 void main()
           ^
0_0_35812416_6778.cpp: In function 'int main()':
0_0_35812416_6778.cpp:14:15: error: 'strlen' was not declared in this scope
   l=strlen(str);
               ^