View Compilation Error

0_0_16879566_23396.cpp: In function 'int main()':
0_0_16879566_23396.cpp:18:21: error: 'k' was not declared in this scope
                 for(k=0;k+j<=t;k+=i*i)
                     ^
0_0_16879566_23396.cpp:19:17: error: 'c' was not declared in this scope
                 c[k+j]+=c1[j];
                 ^