C實現命令行求和

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

extern int str_type_func(char *str);

int main(int argc,char *argv[])
{
        int i = 0;
        int sum_int = 0;
        double sum_d = 0;
        double sum = 0;
        int str_type = 0;
        char *tmp_str = NULL;

        for (i=1; i<argc; i++ )
        {
                tmp_str = argv[i];
                str_type = str_type_func(tmp_str);
                if (1 == str_type)
                        sum_int += atoi(tmp_str);
                else if (2 == str_type)
                        sum_d += atof(argv[i]);
        }

        sum_d += sum_int;

        printf("sum = %.2f\n", sum_d);

        return 0;
}

int str_type_func(char *str)
{
        int len = 0;
        int i = 0;
        int digit_cnt = 0;
        int alpha_cnt = 0;
        int minus_cnt = 0;
        int decimal_cnt = 0;

        len = strlen(str);

        for (i=0; i<len; i++)
        {
                if (isdigit(str[i]) != 0)
                        digit_cnt += 1;
                else if (isalpha(str[i]) != 0)
                        alpha_cnt += 1;
                else if (str[i] == '-' && i==0)
                        minus_cnt = 1;
                else if (str[i] == '-' && i>0)
                        minus_cnt = 10;
                else if (str[i] == '.')
                        decimal_cnt += 1;
        }

        if (alpha_cnt==0 && digit_cnt>0 && minus_cnt<=1 && decimal_cnt==0)
                return 1; //整數
        else if ( alpha_cnt==0 && digit_cnt>0 && minus_cnt<=1 && decimal_cnt==1)
                return 2; //小數
        else
                return 3;
}