Extract Digits From one String

char *str="TakeProfit_II=440"
int value = get_value(str);

...

int get_value(char *str)
{
     char *value_str = new char[10];
     int index1 = 0;
     int index2 = 0;
     int i = 0;
     int val = 0;
     
     while(str[index1] != '=')
     {
          index1++;
     }
     
     for(i = index1+1 ; i < strlen(str) ; i++)
     {
          value_str[index2] = str[i];
          index2++;
     }

     value_str[index2] = NULL;

     val = atoi(value_str);
     delete []value_str;
     return val; 

}