文件操作函数（读写）

文件文本排序：

数组冒泡：

#include<stdio.h>

void swap(int *a,int *b)
{
    int temp = *a;
    *a = *b;
    *b = temp;
}

void bubble(int *p,int n)
{
    int i;
    int j;
    for(i = 0; i < n; i++)
    {
        for(j = 1; j < n - i; j++)
        {
            if(p[j - 1] > p[j])
            {
                swap(&p[j-1],&p[j]);
            }
        }
    }
}

int main()
{
        int arr[10] = {4,6,3,7,8,5,12,67,34,56};
        bubble(arr,10);
        
        int i;
        for(i = 0; i < 10 ; i++)
        {
            printf("%d ",arr[i]);
        }
        printf("
");
        return 0;
}

文件数据排序

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

void swap(int *a,int *b)
{
    int temp = *a;
    *a = *b;
    *b = temp;
}

void bubble(int *p,int n)
{
    int i;
    int j;
    for(i = 0; i < n; i++)
    {
        for(j = 1; j < n - i; j++)
        {
            if(p[j - 1] > p[j])
            {
                swap(&p[j-1],&p[j]);
            }
        }
    }
}

int main()
{
        int array[10] = {0};
        int i;
        char buf[100];        
        int index = 0;
        FILE* p =fopen("./file.txt","r");
        if(NULL == p)
        {
            printf("error
");
        }
        else
        {
            while(!feof(p))
            {
                memset(buf,0,sizeof(buf));
                fgets(buf,sizeof(buf),p);
                array[index] = atoi(buf);
                index++;
            }
            fclose(p);
        }
        index--;
        bubble(array,index);

        p = fopen("./b.txt","w");
        printf("index = %d
",index);
        for(i = 0; i < index ; i++)
        {
            memset(buf,0,sizeof(buf));
            sprintf(buf,"%d
",array[i]);
            fputs(buf,p);
            //printf("%d ",array[i]);
        }
        fclose(p);
        printf("i = %d
",i);
        return 0;
}

如果文件数据过大，就不能在栈中建立一个数组，考虑使用堆

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

void swap(int *a,int *b)
{
    int temp = *a;
    *a = *b;
    *b = temp;
}

void bubble(int *p,int n)
{
    int i;
    int j;
    for(i = 0; i < n; i++)
    {
        for(j = 1; j < n - i; j++)
        {
            if(p[j - 1] > p[j])
            {
                swap(&p[j-1],&p[j]);
            }
        }
    }
}

int main()
{
        int i;
        char buf[100];        
        int index = 0;
        FILE* p =fopen("./file.txt","r");
        if(NULL == p)
        {
            printf("error
");
        }
        //else
        {
            while(!feof(p))
            {
                memset(buf,0,sizeof(buf));
                fgets(buf,sizeof(buf),p);
                index++;
            }
            fclose(p);
        }

        int *array = calloc(sizeof(int),index);
        index = 0;

         p =fopen("./file.txt","r");
        if(NULL == p)
        {
            printf("error
");
        }
        //else
        {
            while(!feof(p))
            {
                memset(buf,0,sizeof(buf));
                fgets(buf,sizeof(buf),p);
                array[index] = atoi(buf);
                index++;
            }
            fclose(p);
        }

        index--;
        bubble(array,index);
    

        p = fopen("./b.txt","w");
        printf("index = %d
",index);
        for(i = 0; i < index ; i++)
        {
            memset(buf,0,sizeof(buf));
            sprintf(buf,"%d
",array[i]);
            fputs(buf,p);
            //printf("%d ",array[i]);
        }
        fclose(p);
        printf("i = %d
",i);
        return 0;
}