not random access iterators for range search

pos25 = find (coll.begin(), coll.end(), //range
25); //value
pos35 = find (coll.begin(), pos25, //range
35); //value
if (pos35 != pos25) {
/*pos35 is in front of pos25
*so, only [pos35,pos25) is valid
*/
...
}
else {
pos35 = find (pos25, coll.end(), //range
35); //value
if (pos35 != pos25) {
/*pos25 is in front of pos35
*so, only [pos25,pos35) is valid
*/
...
}
else {
// both are equal, so both must be end()
...
}
}