c语言中国打开并读取文件

#include <stdio.h>

int main(void)
{
    FILE *fp;  //打开文件前必须要定义FILE*型指针变量 
    
    int lines = 0;
    char name[128];
    double height, weight;
    double hsum = 0, wsum = 0;
    
    if((fp = fopen("hw.dat","r")) == NULL)
        printf("\afile does not exist!\n");
    else
    {
        while(fscanf(fp, "%s%lf%lf", name, &height, &weight) == 3) // fscanf函数用于读取文件，fscanf函数和scanf函数相似，多了一个参数，即流（指针）。
        //fscanf函数的返回值为成功赋值的项目 
        {
            printf("%-8s%8.3f%8.3f\n", name, height, weight);
            lines++;
            hsum += height;
            wsum += weight;
        }
        puts("\n============================\n");
        printf("average: %8.3f%8.3f\n", hsum/lines, wsum/lines);
        fclose(fp);
    }
    return 0;
}