View Compilation Error

0_0_19396956_20142.cpp:2:11: error: '::main' must return 'int'
 void main()
           ^
0_0_19396956_20142.cpp: In function 'int main()':
0_0_19396956_20142.cpp:23:4: error: expected primary-expression before 'else'
    else if(c1==c2)
    ^