编程环境Visual Studio 2017
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#include <stdio.h> #include <stdlib.h> #include <ctype.h> #include <math.h> // practice 1 #define MONTHS 12 #define YEARS 5 void p10_1(void) { const float rain[YEARS][MONTHS] = { {4.3, 4.3, 4.3, 3.0, 2.0, 1.2, 0.2, 0.2, 0.4, 2.4, 3.5, 6.6}, {8.5, 8.2, 1.2, 1.6, 2.4, 0.0, 5.2, 0.9, 0.3, 0.9, 1.4, 7.3}, {9.1, 8.5, 6.7, 4.3, 2.1, 0.8, 0.2, 0.2, 1.1, 2.3, 6.1, 8.4}, {7.2, 9.9, 8.4, 3.3, 1.2, 0.8, 0.4, 0.0, 0.6, 1.7, 4.3, 6.2}, {7.6, 5.6, 3.8, 2.8, 3.8, 0.2, 0.0, 0.0, 0.0, 1.3, 2.6, 5.2} }; int year, month; float subtot, total; printf(" YEAR RAINFALL(inches)\n"); for (year = 0, total = 0; year < YEARS; year++) { for (month = 0, subtot = 0; month < MONTHS; month++) subtot += *(*(rain + year) + month); printf("%5d %15.1f\n", 2010+year, subtot); total += subtot; } printf("\nThe yearly average is %.1f inches.\n\n", total / YEARS); printf("MONTHLY AVERAGE:\n\n"); printf(" Jan Feb Mar Apr May Jun Jul Aug Sep Oct"); printf(" Nov Dec\n"); for (month = 0; month < MONTHS; month++) { for (year = 0, subtot = 0; year < YEARS; year++) subtot += *(*(rain + year) + month); printf("%4.1f", subtot / YEARS); } printf("\n"); return ; } // practice 2 void copy_arr(double target[], double source[], int num) { for (size_t i = 0; i < num; i++) { target[i] = source[i]; } return; } void copy_ptr(double *target, double *source, int num) { for (size_t i = 0; i < num; i++) { *(target + i) = *(source + i); } return; } void copy_ptrs(double *target, double *source_begin, double *source_end) { for (double *i = source_begin; i < source_end; i++) { *target++ = *i; } return; } void p10_2(void) { double source[5] = { 1.1, 2.2, 3.3, 4.4, 5.5 }; double target1[5]; double target2[5]; double target3[5]; copy_arr(target1, source, 5); copy_ptr(target2, source, 5); copy_ptrs(target3, source, source+5); printf("target1:"); for (size_t i = 0; i < 5; i++) { printf(" %.2lf", target1[i]); } printf("\n"); printf("target2:"); for (size_t i = 0; i < 5; i++) { printf(" %.2lf", target2[i]); } printf("\n"); printf("target3:"); for (size_t i = 0; i < 5; i++) { printf(" %.2lf", target3[i]); } printf("\n"); } // practice 3 int max_element(int arr[], int num) { int tmp = arr[0]; for (size_t i = 0; i < num; i++) { if (tmp < arr[i]) { tmp = arr[i]; } } return tmp; } void p10_3(void) { int arr[10] = { 10, 23, 55, 2, 12, 5, 23, 333, 5, 100 }; int result = max_element(arr, 10); printf("The max element of array is %d.\n", result); return; } // practice 4 int max_element_subscript(double arr[], int num) { double tmp = arr[0]; int subscript = 0; for (size_t i = 0; i < num; i++) { if (tmp < arr[i]) { tmp = arr[i]; subscript = i; } } return subscript; } void p10_4(void) { double arr[10] = { 1.23, 202.22, 39.03, 292.11, 3939.22, 30.2, 333.33, 938.2, 391.1, 2.2 }; int result = 0; result = max_element_subscript(arr, 10); printf("The max element subscript of arr is %d\n", result); return; } // practice 5 double diff_max_min(double arr[], int num) { double max = arr[0]; double min = arr[0]; for (size_t i = 0; i < num; i++) { if (max < arr[i]) { max = arr[i]; } if (min > arr[i]) { min = arr[i]; } } return (max - min); } void p10_5(void) { double arr[10] = { 1.23, 202.22, 39.03, 292.11, 3939.22, 30.2, 333.33, 938.2, 391.1, 2.2 }; double result = 0.0; printf("The different of max and min is %.2lf\n", diff_max_min(arr, 10)); return; } // practice 6 void revert_arr(double arr[], int num) { for (size_t i = 0; i < num / 2; i++) { double tmp = arr[i]; arr[i] = arr[num - 1 - i]; arr[num - 1 - i] = tmp; } } void p10_6(void) { double arr[10] = { 1.23, 202.22, 39.03, 292.11, 3939.22, 30.2, 333.33, 938.2, 391.1, 2.2 }; printf("Before revert, the array is:"); for (size_t i = 0; i < 10; i++) { printf(" %.2lf", arr[i]); } printf("\n"); revert_arr(arr, 10); printf(" After revert, the array is:"); for (size_t i = 0; i < 10; i++) { printf(" %.2lf", arr[i]); } printf("\n"); return; } // practice 7 void p10_7(void) { const double rain[YEARS][MONTHS] = { { 4.3, 4.3, 4.3, 3.0, 2.0, 1.2, 0.2, 0.2, 0.4, 2.4, 3.5, 6.6 }, { 8.5, 8.2, 1.2, 1.6, 2.4, 0.0, 5.2, 0.9, 0.3, 0.9, 1.4, 7.3 }, { 9.1, 8.5, 6.7, 4.3, 2.1, 0.8, 0.2, 0.2, 1.1, 2.3, 6.1, 8.4 }, { 7.2, 9.9, 8.4, 3.3, 1.2, 0.8, 0.4, 0.0, 0.6, 1.7, 4.3, 6.2 }, { 7.6, 5.6, 3.8, 2.8, 3.8, 0.2, 0.0, 0.0, 0.0, 1.3, 2.6, 5.2 } }; double rain_cp[YEARS][MONTHS]; for (size_t i = 0; i < YEARS; i++) { copy_arr(rain_cp[i], rain[i], MONTHS); } printf("After copy:\n"); for (size_t i = 0; i < YEARS; i++) { for (size_t j = 0; j < MONTHS; j++) { printf("%.2f ", rain_cp[i][j]); } printf("\n"); } } // practice 8 void p10_8(void) { double arr[10] = { 1.23, 202.22, 39.03, 292.11, 3939.22, 30.2, 333.33, 938.2, 391.1, 2.2 }; double target[3]; copy_ptrs(target, arr+2, arr+5); for (size_t i = 0; i < 3; i++) { printf("%.2lf ", target[i]); } } // practice 9 void copy_arr_2d(double target[][5], double source[][5], int rows) { for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { target[i][j] = source[i][j]; } } return; } void print_arr_2d(double source[][5], int rows) { for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { printf("%.2lf ", source[i][j]); } } printf("\n"); return; } void p10_9(void) { double source[3][5] = { {12.3, 32.1, 31.2, 677.6, 325.6}, {23.1, 568.2, 23.5, 32.4, 88.67}, {235.8, 64.5, 645.23, 2.3, 23.5} }; double target[3][5]; copy_arr_2d(target, source, 3); print_arr_2d(source, 3); print_arr_2d(target, 3); } // practice 10 void arr_add(int target[], int source1[], int source2[], int length) { for (size_t i = 0; i < length; i++) { target[i] = source1[i] + source2[i]; } return; } void p10_10(void) { int source1[4] = { 2, 4, 5, 8 }; int source2[4] = { 1, 0, 4, 6 }; int target[4]; arr_add(target, source1, source2, 4); for (size_t i = 0; i < 4; i++) { printf("%d ", source1[i]); } printf("\n"); for (size_t i = 0; i < 4; i++) { printf("%d ", source2[i]); } printf("\n"); for (size_t i = 0; i < 4; i++) { printf("%d ", target[i]); } printf("\n"); } // practice 11 void arr_x2(int arr[][5], int rows) { for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { arr[i][j] = arr[i][j] * 2; } } return; } void print_int_arr_2d(int arr[][5], int rows) { for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { printf("%d ", arr[i][j]); } printf("\n"); } return; } void p10_11(void) { int source[3][5] = { { 12, 32, 31, 677, 325 }, { 23, 568, 23, 32, 88 }, { 235, 64, 645, 2, 23 } }; printf("Original array:\n"); print_int_arr_2d(source, 3); arr_x2(source, 3); printf("After x2 array:\n"); print_int_arr_2d(source, 3); return; } // practice 12 // 跳过吧，想到的是吧循环抽出来写在函数里，没什么好做的 // practice 13 void enter_arr(double arr[][5], int rows) { for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { scanf_s("%lf", &arr[i][j]); getchar(); } } return; } double cal_avg_1d(double arr[], int cols) { double sum = 0.0; for (size_t i = 0; i < cols; i++) { sum += arr[i]; } return (sum / cols); } double cal_avg_2d(double arr[][5], int rows) { double sum = 0.0; for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { sum += arr[i][j]; } } return (sum / (5 * rows)); } double arr_max_element(double arr[][5], int rows) { double max = 0.0; for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { if (max < arr[i][j]) { max = arr[i][j]; } } } return max; } void print_double_2d(double arr[][5], int rows) { for (size_t i = 0; i < rows; i++) { for (size_t j = 0; j < 5; j++) { printf("%lf ", arr[i][j]); } printf("\n"); } return; } void p10_13(void) { double arr[3][5]; printf("Enter 15 double number:"); enter_arr(arr, 3); for (size_t i = 0; i < 3; i++) { printf("average of row %d is %lf\n", i, cal_avg_1d(arr[i], 5)); } printf("average of 15 double numbers is %lf\n", cal_avg_2d(arr, 3)); printf("The max element of array is %lf\n", arr_max_element(arr, 3)); return; } // practice 14 // vs2017不知道怎么设置变成数组，大概跟practice 13差不多 int main(int argc, char **argv) { p10_13(); while (getchar()) { } return 0; } |
此文为博主原创文章，转载请注明出处
VS是不支持部分c99的标准，变长数组VLA就是其中之一。
第十二题我觉得除了循环抽出来，写在函数里。我觉得还涉及到
数组在函数中的复制 
数组在函数中的叠加 
还用到数组的返回值。我觉得这是一道很值得做的题。其他题都比较简单。这道看起来简单，但做起来很训练思维。我是晚上做的，早上起来恍然大悟。也可以算是思考了一晚上吧！楼主的这套答案真的太棒了。让我从小白到进阶，现在在学数据结构。争取考上研究生！
同学，请问考上了吗
我觉得博主13题的答案有误。arr_max_element函数中不应该初始化max =0.0,题目中并没有要求输入正数，这意味着如果都输入负数的话max将是一个数组中不存在的数。应该改为max = arr [0] [0] 更合适。
第六题错了啊，输出结果不对，怎么写的，用的什么算法这是？？？？？？？？