View Compilation Error

0_0_12021532_16534.cpp: In function `int find(int)':
0_0_12021532_16534.cpp:20: error: no match for 'operator!=' in 'x != f[x]'
0_0_12021532_16534.cpp:22: error: cannot convert `st' to `int' for argument `1' to `int find(int)'
0_0_12021532_16534.cpp:24: error: cannot convert `st' to `int' in return
0_0_12021532_16534.cpp: In function `int fun(int, int)':
0_0_12021532_16534.cpp:33: error: no match for 'operator=' in 'f[x] = y'
0_0_12021532_16534.cpp:5: note: candidates are: st& st::operator=(const st&)
0_0_12021532_16534.cpp: In function `int main()':
0_0_12021532_16534.cpp:45: error: no match for 'operator=' in 'f[i] = i'
0_0_12021532_16534.cpp:5: note: candidates are: st& st::operator=(const st&)
0_0_12021532_16534.cpp:55: error: `p' undeclared (first use this function)
0_0_12021532_16534.cpp:55: error: (Each undeclared identifier is reported only once for each function it appears in.)