Linux Linux程序练习三

/*
index1 = 45
index2 = 36
index3 = 231
index4 = 43
index5 = 100
index6 = 123
index7 = 51
 *
 *
 通过读取读取c.txt文件内容中等号右值，并将右值最大值，最小值和平均值打印到屏幕。
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

//删除'\n'
void removeenter(char * str)
{
    if (str == NULL)
    {
        printf("传入参数不可以为空！\n");
        return;
    }
    char * temp = str;
    while (*temp)
    {
        if (*temp == '\n')
        {
            *temp = '\0';
        }
        temp++;
    }
}

//获取数字
char * getnum(char * str)
{
    if (str == NULL)
    {
        printf("传入参数不可以为空！\n");
        return NULL;
    }
    str=strchr(str,'=');
    while (*str)
    {
        if (*str>'0'&&*str<'9')
        {
            break;
        }
        str++;
    }
    return str;
}

//read the file
void readfile(char *path, int *arr, int *len)
{
    if (path == NULL || arr == NULL || len == NULL)
    {
        printf("传入参数不可以为空！\n");
        return;
    }
    //define the file stream
    FILE * pfr = NULL;
    //open the file in read mode
    pfr = fopen(path, "r");
    //judge
    if (pfr == NULL)
    {
        printf("read the file failed ! error msg:%s\n", strerror(errno));
        return;
    }
    //read the file
    char buf[50] = { 0 };
    int index = 0;
    while (fgets(buf, sizeof(buf), pfr))
    {
        //fgets()函数读取字符串时，会读取'\n'
        removeenter(buf);
        arr[index++] = atoi(getnum(buf));
        memset(buf, 0, sizeof(buf));
    }
    *len = index;
    //close the file
    if (pfr)
    {
        fclose(pfr);
        pfr = NULL;
    }
}

void SelectionSort(int *arr, int len, int *max, int *min, double *avg)
{
    if (arr == NULL || max == NULL || min == NULL || avg == NULL)
    {
        printf("传入参数不可以为空！\n");
        return;
    }
    int i = 0, j = 0, k = 0, temp = 0;
    for (; i < len; i++)
    {
        k = i;
        for (j = i + 1; j < len; j++)
        {
            if (arr[k] > arr[j])
            {
                k = j;
            }
        }
        if (k != i)
        {
            temp = arr[i];
            arr[i] = arr[k];
            arr[k] = temp;
        }
    }
    *max = arr[len - 1];
    *min = arr[0];
    temp = 0;
    printf("排序之后的\n");
    for (i = 0; i < len; i++)
    {
        printf("%d\n", arr[i]);
        temp += arr[i];
    }
    printf("排序在此结束\n");
    *avg = temp / len;
}

int main(int arg, char * args[])
{
    if (arg < 2)
    {
        printf("请输入一个参数！\n");
        return 0;
    }
    int arr[50] = { 0 };
    int len = 0;
    int maxnum = 0;
    int minnum = 0;
    double avgnum = 0;
    readfile(args[1], arr, &len);
    SelectionSort(arr, len, &maxnum, &minnum, &avgnum);
    printf("最大值：%d\n", maxnum);
    printf("最小值：%d\n", minnum);
    printf("平均值：%lf\n", avgnum);
    return 0;
}