Help me with this error Please

How to pass string(arr) to function and perform operation.

i m receiving an error:
....main.cpp|35|error: cannot convert 'std::string' to 'char*' for argument '1' to 'int check(char*)'|

Code:

---

#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

int check(char *arr);

int main()
{
    string arr;
    int cont=1;
    int chck;

    while (1)
    {
        cout << "Enter your Date of Birth (Format: DD/MM/YYYY e.g: 11/09/1984): ";
        getline(cin,arr);
        if (arr == "0")
        {
            cout << "Thankyou for using... :)";
            exit(1);
        }
        else
        {

            if (arr.length() != 10 )
            {
                cout << "Syntax Error! Please follow the syntax\n\n";

                continue;
            }



            if(check(arr) != 0)    // Checking the Syntax
            {
                if (check(arr) == 1)
                {
                    cout << "\nError in Date. Please try again and follow the syntax\n";
                }
                if (check(arr) == 2)
                {
                    cout << "\nError in Month. Please try again and follow the syntax\n";
                }
                if (check(arr) == 3)
                {
                    cout << "\nError in Year. Please try again and follow the syntax\n";
                }
                if (check(arr) == 4)
                {
                    cout << "\nError in Syntax. Please try again and follow the syntax\n";
                }
                cont=1;
            }



        }
    }

    return 0;
}

int check(char arr[10])
{
    if ((int)arr[0] <= 47 || (int)arr[0] >= 50 || (int)arr[1] <= 47 || (int)arr[1] >= 57 )
    {
        return 1;// Date problem
    }

    if ( (int)arr[3] == 47 && (int)arr[4] <= 48 || (int)arr[4] >= 57)
    {
        return 2; // month problem
    }

    if( (int)arr[3] == 48 && (int)arr[4] <= 47 || (int)arr[4] >= 49)
    {
        return 2; // month problem
    }

    if( (int)arr[6] <= 48 || (int)arr[6] >= 49)
    {
        return 3; // Year problem
    }
    if( (int)arr[2] == '/' && (int)arr[5] == '/')
    {
        return 4;
    }

    return 0;
}

---

Pass

Code:

---

arr.c_str()

---

Instead.

Also, consider using constants instead of magic numbers.

magic nos?? :\ ??

error: ...\main.cpp|34|error: invalid conversion from 'const char*' to 'char*'|

Code:

---

#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

int check(char *arr);

int main()
{
    string arr;
    int cont=1;
    int chck;

    while (1)
    {
        cout << "Enter your Date of Birth (Format: DD/MM/YYYY e.g: 11/09/1984): ";
        getline(cin,arr);
        if (arr == "0")
        {
            cout << "Thankyou for using... :)";
            exit(1);
        }
        else
        {

            if (arr.length() != 10 )
            {
                cout << "Syntax Error! Please follow the syntax\n\n";

                continue;
            }


            chck = check(arr.c_str());
            if(chck != 0)    // Checking the Syntax
            {
                if (chck == 1)
                {
                    cout << "\nError in Date. Please try again and follow the syntax\n";
                }
                if (chck == 2)
                {
                    cout << "\nError in Month. Please try again and follow the syntax\n";
                }
                if (chck == 3)
                {
                    cout << "\nError in Year. Please try again and follow the syntax\n";
                }
                if (chck == 4)
                {
                    cout << "\nError in Syntax. Please try again and follow the syntax\n";
                }
                cont=1;
            }



        }
    }

    return 0;
}

int check(char arr[10])
{
    if ((int)arr[0] <= 47 || (int)arr[0] >= 50 || (int)arr[1] <= 47 || (int)arr[1] >= 57 )
    {
        return 1;// Date problem
    }

    if ( (int)arr[3] == 47 && (int)arr[4] <= 48 || (int)arr[4] >= 57)
    {
        return 2; // month problem
    }

    if( (int)arr[3] == 48 && (int)arr[4] <= 47 || (int)arr[4] >= 49)
    {
        return 2; // month problem
    }

    if( (int)arr[6] <= 48 || (int)arr[6] >= 49)
    {
        return 3; // Year problem
    }
    if( (int)arr[2] == '/' && (int)arr[5] == '/')
    {
        return 4;
    }

    return 0;
}

---

Change the prototype and definition to use:

Code:

---

int check(const char* arr)

---

Btw.. Why not use strings there too ? That would make it nicer to read.

Also..try fixing these warnings:

Quote:

---

a.cpp: In function ‘int main()’:a.cpp:11:9: warning: variable ‘cont’ set but not used [-Wunused-but-set-variable]
a.cpp: In function ‘int check(const char*)’:
a.cpp:71:67: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
a.cpp:76:66: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]

---

(Though it may not seem important, it could turn out to be)

> if ((int)arr[0] <= 47 || (int)arr[0] >= 50 || (int)arr[1] <= 47 || (int)arr[1] >= 57 )
47 etc are magic numbers.

Constants are both more portable and more readable, as in
if ((int)arr[0] < '0' || (int)arr[0] >= '3' || (int)arr[1] < '0' || (int)arr[1] > '9' )

Change
int check(char *arr);
to
int check(const std::string& arr);