View Compilation Error

0_0_27068873_10260.cpp: In function 'int main()':
0_0_27068873_10260.cpp:34:5: error: 'ans' was not declared in this scope
     ans+=num[M+sum];
     ^
0_0_27068873_10260.cpp:39:17: error: 'ans' was not declared in this scope
    printf("%d ",ans);
                 ^