Смысл кода - C (СИ)

bool is_valid_formatting(int num_args_read, int num_args_needed){
    
    char new_line = '\n';
    bool is_valid = true; //assume the format is correct
    if(num_args_read != num_args_needed){ //didn't fill in all the format specifiers
        is_valid = false;//format is not correct
    }

    do{
        scanf("%c", &new_line); //read the next character from the standard input
        if(!isspace(new_line)){ //if it isn't white space
            is_valid = false; //extra stuff there so format isn't valid
        }
    }while(new_line != '\n'); //keep reading characters until you reach the new line character
    return is_valid;
}
double get_valid_payment(){
    double num;
    int num_args_read;
    do{
        printf("Enter how much money you will be putting towards loans/retirement each month: ");
        num_args_read = scanf("%lf", &num);
    }while(!(is_valid_formatting(num_args_read, 1)));
    
    return num;
}
int main(){
payment = get_valid_payment;

do{
        scanf("%c", &new_line); //read the next character from the standard input
        if(!isspace(new_line)){ //if it isn't white space
            is_valid = false; //extra stuff there so format isn't valid
        }
    }while(new_line != '\n'); //keep reading characters until you reach the new line character
    return is_valid;