View Compilation Error

0_0_34611282_19612.cpp: In function 'int main()':
0_0_34611282_19612.cpp:94:20: error: 'a' was not declared in this scope
         scanf("%d",a+i);
                    ^
0_0_34611282_19612.cpp:114:16: error: 'a' was not declared in this scope
             if(a[x]){
                ^
0_0_34611282_19612.cpp:123:13: error: 'a' was not declared in this scope
             a[x]=y;
             ^