sorting - C++ - invalid operands to binary expression -

i trying use std::sort sort list of structs. getting error:

invalid operands binary expression ('std::__1::__list_iterator<process, void *>' , 'int') __sort3<_compare>(__first, __first+1, __j, __comp);

struct:

struct process {    int process_id;    int cpu_cycles;    int mem_footprint; }; 

main function:

int main() {      list<process> process_list;      init_process_list(process_list);     sort(process_list.begin(), process_list.end(), compare_pid);  } 

init_process_list:

void init_process_list(list<process> &p_list) {      cout << "\n>> generating process list...";      generator generate; // random number generator class     process p;      for(int = 0; < process_count; i++) {         p.process_id = i;         p.cpu_cycles = generate.rand_num_between(cycle_lbound, cycle_ubound);         p.mem_footprint = generate.rand_num_between(mem_lbound, mem_ubound);         p_list.push_back(p);     }      cout << "done" << endl;  } 

compare_pid:

bool compare_pid(process &lhs, process &rhs) {      return lhs.cpu_cycles < rhs.cpu_cycles;   } 

i want sort process items in list cpu_cylcles value in ascending order. made compare_pid function takes in 2 process , returns boolean. can't figure out error is. can please help?

invalid operands binary expression
('std::__1::__list_iterator' , 'int')
__sort3<_compare>(__first, __first+1, __j, __comp);

alright, third line of code somwhere in std::sort. operator there +. expression error __first+1 __first list<process>::iterator. list iterators not have iterator+int overload, because bidirectional iterators, not random access.

you cannot call std::sort on std::list. use std::vector instead, or container random access iterators.