C语言从文件中读写格式化数据

 从图 1 所示的文件 fin.txt 中读取学生姓名、身高和体重，计算并显示它们的平均值，并且将显示结果保存到文件 fout.txt 中。

图 1：输入输出文件示例

C语言代码清单 1：读取学生姓名、身高和体重，计算并显示它们的平均值

#include <stdio.h>
#include <stdlib.h>
int main( )
{
    int num = 0;
    FILE *fp1,*fp2;
    char name[100];
    double height,weight,hSum=0.0,wSum=0.0;
    if((fp1 = fopen("fin.txt","r")) == NULL)
        printf("\a文件fin.txt打开失败！\n");
    else{
        fp2 = fopen("fout.txt","w");
        while(fscanf(fp1,"%s%lf%lf",name,&height,&weight) == 3){
            printf("%-10s %5.1f %5.1f\n",name,height,weight);
            fprintf(fp2,"%-10s %5.1f %5.1f\n",name,height,weight);
            num++;
            hSum += height;
            wSum += weight;
        }
        printf("----------------------\n");
        printf("平均       %5.1f %5.1f\n",hSum/num,wSum/num);
        fprintf(fp2,"----------------------\n");
        fprintf(fp2,"平均       %5.1f %5.1f\n",hSum/num,wSum/num);
        fclose(fp1); fclose(fp2);
    }
    system("pause");
    return 0;
}

运行结果为：

Linda      155.0  40.5
Mary       157.0  39.5
Tony       150.0  38.3
Sala       158.0  42.8
----------------------
平均       155.0  40.3