my computer won't accept s.length, but other compilers do

Question

Playing with some functions and my computer/NetBeans cannot seem to run my code, even though it can be run in different compilers. Here's my function (keep in mind this isn't my whole project I do have an int main()):

#include <iostream>
#include <iomanip>
#include <string>
#include <iterator>
#include <cstdlib>
#include <ctime>
#include <windows.h>
using namespace std;
void convert (string& s){ //Creating a function that makes a variable lower case
    for(int i=0; i<s.length(); i++){ 
        s[i] = tolower(s[i]); //tolower lets me change to lower case
    }
}

The error I'm getting is: "cannot resolve identifier length". if you need to see my whole project please ask, I don't mind, just think its a waste of time if it doesn't matter. I'm using NetBeans 8.2, thanks in advance

What happens if you make a program with **only** that function and an empty `int main() {}`? — Galik, Jan 12 '18 at 04:49
What happens if *explicitly* using `std::string` as the type? — user2864740, Jan 12 '18 at 04:52
Try looking this https://stackoverflow.com/questions/14913243/netbeans-7-2-shows-unable-to-resolve-identifier-although-build-is-successful — Aakash Deep, Jan 12 '18 at 04:54
@user2864740 I'm sorry i'm new at this, how would i do that? — Aidan Christopher, Jan 12 '18 at 05:10
@AakashDeep That worked, but now it's building fine, but cant run. It's saying: "RUN FAILED (exit value -1, 073, 741, 511, total time: 69ms)" — Aidan Christopher, Jan 12 '18 at 05:13
@AidanChristopher Try searching this error in stackoverflow, you may find something. — Aakash Deep, Jan 12 '18 at 05:19
@CraigYoung he _did_ provide a Minimal, Complete, and Verifiable example. — Jabberwocky, Jan 12 '18 at 08:02
@MichaelWalz Are you claiming all the includes are _required_ to reproduce the problem? If not, then it's blatantly obviously ***not minimal***. By OP's own admission the code presented lacks `main`; hence it's ***not complete***. I cannot confirm it's verifiability; that _might_ need even ***more*** information such as how the compiler is actually called. MCVE is not a bunch of arbitrary letters meaning a little bit of code. Follow the link above to learn more. — Disillusioned, Jan 12 '18 at 11:43

score 1 · Answer 1 · answered Jan 12 '18 at 06:48

You can try size() instead of length() . For string in C++ there's no notable difference between them but size() is used in other STL containers like map, vector etc. too. So generally, people use size() function.

Usage is same like length(), i < s.size()

Jive Dadson · Answer 2 · 2018-01-12T10:20:13.737

It looks as though the implementation of std::string has omitted the function length(); BTW, it does not return int, so you should get a warning ticket for that. In future, please post a complete program, including main().

Workaround the old way;

#include <string>

void convert(std::string& s) { //Creating a function that makes a variable lower case
    const size_t sz = s.size();

    for (size_t i = 0; i<sz; ++i) {
        s[i] = tolower(s[i]); //tolower lets me change to lower case
    }
}

int main() {
    std::string s("AbCdEf");
    convert(s);
    return 0;
}

Newfangled way...

#include <string>

void convert(std::string& s) { //Creating a function that makes a variable lower case
    for (char &ch : s) {
        ch = tolower(ch); //tolower lets me change to lower case
    }
}

int main() {
    std::string s("AbCdEf");
    convert(s);
    return 0;
}

Even newfangleder way...

#include <algorithm>

void convert(std::string& s) { //Creating a function that makes a variable lower case
       std::transform(std::begin(s), std::end(s), std::begin(s), ::tolower);
}

my computer won't accept s.length, but other compilers do

2 Answers2