c primer plus第10章课后题第12题：编写一个程序，提示用户输入3个数集，每个数集包括5个double值

好久没时间学c语言了，最近重新捡起来，之前这道题卡了很久，可能是我没读懂题，这次回来几分钟就搞定了。果然学习还是要持续，不然卡在哪里都不记得，起不到总结经验的效果了。希望看到的朋友能引以为戒，保持学习的习惯。

编写一个程序，提示用户输入3个数集，每个数集包括5个double值，实现一下功能：
a.储存二维数组
b.计算每个数集的平均值
c.计算所有数的平均数
d.找出最大值
e.打印结果

#include "stdio.h"
#define ROWS 3
#define COLS 5
double cal_avg_row(double ar[][COLS],int row);
double cal_avg_all(double ar[][COLS],int row);
double max_value(double ar[][COLS],int row);


int main(void){
    printf("Please input 3 sets of numbers，which have 5 numbers in each set.n");
    
    int i,j;
    double set1[COLS];
    double set2[COLS];
    double set3[COLS];
    
    double allsum=0;
    double maxvalue = 0;
    double array[ROWS][COLS];
    double avg_row[ROWS];
    
    printf("the first set:");
    for (i=0; i
        scanf("%lf",&set1[i]);
    }
    printf("the second set:");
    for (i=0; i
        scanf("%lf",&set2[i]);
    }
    printf("the third set:");
    for (i=0; i
        scanf("%lf",&set3[i]);
    }
    
    printf("a.将输入的三个数集储存为二维数组n");
    printf("b.计算所有数值的平均数n");
    printf("c.找出所有数值的最大值n");
    printf("d.打印出结果n");
    printf("请输入要实现的功能：n");
    char func;
    while (scanf("%s",&func) != EOF) {
        if(func >= 'a' && func <= 'e'){
            switch (func) {
                case 'a':
                    for(i=0 ; i
                        array[0][i] = set1[i];
                        }
                    for(i=0 ; i
                        array[1][i] = set2[i];
                    }
                    for(i=0 ; i
                        array[2][i] = set3[i];
                    }
                    printf("save done.n");
                    break;
                case 'b':
                    for(i=0;i
                        avg_row[i] = cal_avg_row(array, i);
                    }
                    printf("calculate done.n");
                    break;
                case 'c':
                    allsum =cal_avg_all(array, ROWS);
                    printf("calculate done.n");
                    break;
                case 'd':
                    maxvalue = max_value(array, ROWS);
                    printf("calculate done.n");
                    break;
                case 'e':
                    for(i=0;i
                        printf("the average of the %d row is %.2lf.n",i,avg_row[i]);
                    }
                    printf("the average of all numbers is %.2lf.n",allsum);
                    printf("the max value is %.2lf.n",maxvalue);
                default:
                    printf("Done.");
                    break;
            }
        }
    }
    

    return 0;
}

double cal_avg_row(double ar[][COLS],int row){
    int i;
    double sum = 0;
    double avg = 0;
    
    for(i=0; i
            sum += ar[row][i];
        }
    avg = sum/COLS;
    return avg;
}

double cal_avg_all(double ar[][COLS],int row){
    int i,j;
    double allSum = 0 ;
    double avg = 0;
    for(i=0 ; i
        for(j=0 ; j
    int i,j;
    double max = 0 ;
    for(i=0 ; i
        for(j=0 ; j max)
                max = ar[i][j];
    }
    return max;
}

Please input 3 sets of numbers，which have 5 numbers in each set.
the first set:1.1 2.1 3.1 4.1 5.1
the second set:2.1 3.1 4.1 5.1 6.1
the third set:3.1 4.1 5.1 6.1 7.1
a.将输入的三个数集储存为二维数组
b.计算所有数值的平均数
c.找出所有数值的最大值
d.打印出结果
请输入要实现的功能：
a
save done.
b
calculate done.
c
calculate done.
d
calculate done.
e
the average of the 0 row is 3.10.
the average of the 1 row is 4.10.
the average of the 2 row is 5.10.
the average of all numbers is 4.10.
the max value is 7.10.
Done.