View Compilation Error

0_0_27374015_3958.cpp: In function 'void build(int, int, int)':
0_0_27374015_3958.cpp:42:12: error: 'a' was not declared in this scope
   t[i].sum=a[l];
            ^
0_0_27374015_3958.cpp: In function 'int main()':
0_0_27374015_3958.cpp:88:4: error: 'a' was not declared in this scope
    a[i]=read();
    ^