View Compilation Error

0_0_36883758_6724.cpp: In function 'int main()':
0_0_36883758_6724.cpp:42:4: error: 'f' was not declared in this scope
    f[i]=i;
    ^
0_0_36883758_6724.cpp:72:5: error: 'f' was not declared in this scope
     f[fv]=u; 
     ^