自学C第18天

C primer plus

第10章

第13题：

#include <stdio.h>

void get_arr(double ar[][5]);

void get_aver(double ar[][5]);

void get_avet(double ar[][5]);

void get_max(double ar[][5]);

int main(void) {

       double list[3][5];

       get_arr(list);

       get_aver(list);

       get_avet(list);

       get_max(list);

       return 0;

}

void get_arr(double ar[][5]) {

       double a;

       int i=0,j=0;

       printf("Please enter 5 numbers:\n");

       while (i !=3 && scanf("%lf", &a) == 1) {

              ar[i][j++] = a;

              if (j == 5 ) {

                     j = 0;

                     i++;

                     printf("Next enter:"); #注：这个Next enter 会多打印一次，换成for循环应该可以解决 但不影响结果，暂时就这样了

              }

             

       }

       printf("Now the array is:\n");

       for (i = 0; i < 3; i++) {

              putchar('\n');

              for (j = 0; j < 5; j++) {

                     printf("%g ", ar[i][j]);

              }

       }

}

void get_aver(double ar[][5]) {

       int r;

       int i = 0,j = 0;

       double tot = 0;

       double ave = 0;;

       printf("Please choose the row you want to count:");

       while (scanf("%d", &r) == 1) {

              switch (r) {

              case 1:

                     i = 0;

                     for (j = 0; j < 5; j++) {

                            tot += ar[i][j];

                     }

                     ave = tot / 5;

                     printf("The average number for the %d row is %g\n", i + 1, ave);

                     tot = 0;

                     printf("Enter again(q to quit):");

                     break;

              case 2:

                     i = 1;

                     for (j = 0; j < 5; j++) {

                            tot += ar[i][j];

                     }

                     ave = tot / 5;

                     printf("The average number for the %d row is %g\n", i + 1, ave);

                     tot = 0;

                     printf("Enter again(q to quit):");

                     break;

              case 3:

                     i = 2;

                     for (j = 0; j < 5; j++) {

                            tot += ar[i][j];

                     }

                     ave = tot / 5;

                     printf("The average number for the %d row is %g\n", i + 1, ave);

                     tot = 0;

                     printf("Enter again(q to quit):");

                     break;

              default:

                     printf("Enter a number between 1~3:");

                     break;

              }

       }

}

void get_avet(double ar[][5]) {

       int i, j;

       double tot = 0;

       double ave = 0;

       for (i = 0; i < 3; i++) {

              for (j = 0; j < 5; j++) {

                     tot += ar[i][j];

              }

       }

       ave = tot / 15;

       printf("The average number for the whole array is %g\n", ave);

}

void get_max(double ar[][5]) {

       double max;

       int i, j;

       max = ar[0][0];

       for (i = 0; i < 3; i++) {

              for (j = 0; j < 5; j++) {

                     if (max < ar[i][j])

                            max = ar[i][j];

              }

       }

       printf("The max number in this array is %g", max);

}