remove_if() Function in C++

This C++ program demonstrates the remove_if() algorithm. The program creates a vector of strings and removes elements whose first letter is ‘A’ using predicate which is passed as a parameter to the remove_if algorithm which removes elements for which the predicate returns true.

Here is the source code of the C++ program which demonstrates the remove_if() algorithm. The C++ program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C++ Program to demonstrate remove_if algorithm

```
 */
```
```
#include <iostream>
```
```
#include <functional>
```
```
#include <vector>
```
```
#include <algorithm>
```
```
 
```

typedef std::vector<std::string>::iterator iterator;

```
 
```

struct startsWithA : public std::unary_function<std::string, bool> {

```
    bool operator() (std::string s)
```
```
    {
```
```
        if(s[0] == 'A')
```
```
        {
```
```
            return true;
```
```
        }
```
```
        else
```
```
            return false;
```
```
    }
```
```
};
```
```
 
```
```
void print(iterator b, iterator e)
```
```
{
```
```
    iterator i;
```
```
    for(i = b; i != e; i++)
```
```
    {
```
```
        std::cout << *i << "    ";
```
```
    }
```
```
    std::cout << std::endl;
```
```
}
```
```
 
```
```
int main()
```
```
{
```
```
    startsWithA s;
```
```
    std::vector<std::string> v;
```
```
    v.push_back("China");
```
```
    v.push_back("India");
```
```
    v.push_back("Atlanta");
```
```
    v.push_back("Bolivia");
```
```
    v.push_back("Australia");
```
```
    v.push_back("Pakistan");
```
```
 
```
```
    std::cout << "Vector : ";
```
```
    print(v.begin(), v.end());
```

    iterator i = remove_if(v.begin(), v.end(), s);

```
    std::cout << "Vector : ";
```
```
    print(v.begin(), i);
```
```
}
```

$ a.out
Vector : China    India    Atlanta    Bolivia    Australia    Pakistan    
Remove countries starting with 'A'  
Vector : China    India    Bolivia    Pakistan

Sanfoundry Global Education & Learning Series – 1000 C++ Programs.

If you wish to look at all C++ Programming examples, go to C++ Programs.

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