C++：删除字符串中的所有空格操作 代码冗余

如下三行代码没用：

#define _CRT_SECURE_NO_WARNINGS

 if (it == (*str).end())
            break;

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<string.h>
#include<string>
#include<algorithm>
using namespace std;

string del_space(string *str) {
    string::iterator it = (*str).begin();
    while ((it = find(it, (*str).end(), ' ')) != (*str).end())
    {
        (*str).erase(it);
        if (it == (*str).end())
            break;
    }
    return *str;
}

#include <iostream>
using namespace std;
void trim(string &s)
{
    int index = 0;
    if( !s.empty())
    {
        while( (index = s.find(' ',index)) != string::npos)
        {
            s.erase(index,1);
        }
    }
 
}
int main()
{
    
    cout << "-------------------------------------" << endl;
 
    string pri = "  7ter   09, jdhfd iere*- ddw     jjdjjdj     ";
    cout << "src string is : \"" << pri << "\"" << endl;
    trim(pri);
    cout << "after string is : \"" << pri << "\"" << endl;
 
    cout << "-------------------------------------" << endl;
 
    return 0;
}