c++ - Modifying pointer value -

i having trouble work assigned schooling. told write program modifies char. can fine. cannot how work pointers. i've researched this, , found solutions. don't meet assignment's needs. told define function this:

int stripwhite(char *userinput) 

so did. problem is, believe makes copy of value. , not modify actual value. here code picked out of program:

inside main, declare char, , use cin.getline collect input. call stripwhite. cout char. value never changes. assignment says stripwhite needs defined above. @ lose here. help?

char userinput[100]; int spaces = 0; cin.getline(userinput,99); spaces = stripwhite(userinput); cout << userinput; 

your function takes character pointer. based on function name , usage, function presumably intended take character buffer input , remove spaces while returning number of spaces removed.

so basically, have iterate through buffer, , move down contents while skipping spaces. easiest way maintain 2 pointers , copy 1 other.

here's how i'd (warning, not tested). since it's assignment you'll want write own code, example clear misconceptions have.

int stripwhite(char* userinput){      auto inpos = userinput;     auto outpos = userinput;     int count = 0;      while(*inpos){         if(*inpos != ' '){             *outpos = *inpos;             ++outpos;         } else {count++;}         ++inpos;     }      *outpos = '\0';     return count; }