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  1. //動態配置結構陣列，
  2. //讓使用者輸入n後，
  3. //先讓使用者依序輸入n個學生姓名、身高、體重
  4. //算出身高及體重平均，並輸出平均
  5. //最後再輸出身高或體重任一項(一項兩項都可以)低於平均的學生姓名
  6. //名字最長不會超過20字元
  7.  
  8. //承上題，
  9. //輸入改為由檔案輸入
  10. //輸出改為輸出至檔案
  11. //程式流程：
  12. //先後讀取輸入檔名與輸出檔名後，過程如上題，
  13. //檔名不會超過50字元，程式畫面如下圖，
  14. //讀入檔名時請分兩次（兩次 gets 或 scanf）
  15.  
  16. //測試資料可以在課程網頁下載
  17. //內容有：
  18. //輸入檔：可用複製貼上至黑黑的那個視窗
  19. //輸出檔：答案，請仔細比較
  20.  
  21.  
  22. #include <stdio.h>
  23. #include <stdlib.h>
  24.  
  25. struct student{
  26.     	char name[21]; 
  27. 		int height, weight;
  28. 	};
  29.  
  30. int main(){
  31.     FILE *in, *out;  
  32. 	int i, n;
  33. 	char str[51], string[51];
  34.     double sum_h = 0, sum_w = 0, H_avg, W_avg;
  35.  
  36.     printf("Input file:%s", str);
  37.     scanf("%s", &str);
  38.  
  39.     in = fopen(str, "r");  //
  40.  
  41.    	if (in == NULL) {
  42.         printf("open input file failed!\n");
  43.         return 0;
  44.     }
  45.  
  46.     printf("Output file:%s", string);
  47.     scanf("%s", &string);
  48.  
  49.     out = fopen(string, "w"); //
  50.  
  51. 	fscanf(in, "%d", &n);
  52.  
  53. 	struct student *a = (struct student *)malloc(sizeof(struct student)*n);
  54.  
  55. 	for (i = 0; i < n; i++){
  56. 	    fscanf(in, "%s %d %d", a[i].name, &a[i].height, &a[i].weight);
  57. 	}
  58.  
  59. 	for (i = 0; i < n; i++){
  60.         sum_h += a[i].height;
  61. 	    sum_w += a[i].weight;
  62. 	}
  63.  
  64. 	H_avg = sum_h / n;
  65. 	W_avg = sum_w / n;
  66.  
  67. 	fprintf(out, "H_avg:%.2lf\n", H_avg);
  68. 	fprintf(out, "W_avg:%.2lf\n", W_avg);
  69.  
  70.     for (i = 0; i < n; i++){
  71. 		if(a[i].height < H_avg || a[i].weight < W_avg){
  72. 			fprintf(out, "%s\n", a[i].name);
  73. 	//動態配置結構陣列，
  74. //讓使用者輸入n後，
  75. //先讓使用者依序輸入n個學生姓名、身高、體重
  76. //算出身高及體重平均，並輸出平均
  77. //最後再輸出身高或體重任一項(一項兩項都可以)低於平均的學生姓名
  78. //名字最長不會超過20字元
  79.  
  80. //承上題，
  81. //輸入改為由檔案輸入
  82. //輸出改為輸出至檔案
  83. //程式流程：
  84. //先後讀取輸入檔名與輸出檔名後，過程如上題，
  85. //檔名不會超過50字元，程式畫面如下圖，
  86. //讀入檔名時請分兩次（兩次 gets 或 scanf）
  87.  
  88. //測試資料可以在課程網頁下載
  89. //內容有：
  90. //輸入檔：可用複製貼上至黑黑的那個視窗
  91. //輸出檔：答案，請仔細比較
  92.  
  93.  
  94. #include <stdio.h>
  95. #include <stdlib.h>
  96.  
  97. struct student{
  98.     	char name[21]; 
  99. 		int height, weight;
  100. 	};
  101.  
  102. int main(){
  103.     FILE *in, *out;  
  104. 	int i, n;
  105. 	char str[51], string[51];
  106.     double sum_h = 0, sum_w = 0, H_avg, W_avg;
  107.  
  108.     printf("Input file:%s", str);
  109.     scanf("%s", &str);
  110.  
  111.     in = fopen(str, "r");  //
  112.  
  113.    	if (in == NULL) {
  114.         printf("open input file failed!\n");
  115.         return 0;
  116.     }
  117.  
  118.     printf("Output file:%s", string);
  119.     scanf("%s", &string);
  120.  
  121.     out = fopen(string, "w"); //
  122.  
  123. 	fscanf(in, "%d", &n);
  124.  
  125. 	struct student *a = (struct student *)malloc(sizeof(struct student)*n);
  126.  
  127. 	for (i = 0; i < n; i++){
  128. 	    fscanf(in, "%s %d %d", a[i].name, &a[i].height, &a[i].weight);
  129. 	}
  130.  
  131. 	for (i = 0; i < n; i++){
  132.         sum_h += a[i].height;
  133. 	    sum_w += a[i].weight;
  134. 	}
  135.  
  136. 	H_avg = sum_h / n;
  137. 	W_avg = sum_w / n;
  138.  
  139. 	fprintf(out, "H_avg:%.2lf\n", H_avg);
  140. 	fprintf(out, "W_avg:%.2lf\n", W_avg);
  141.  
  142.     for (i = 0; i < n; i++){
  143. 		if(a[i].height < H_avg || a[i].weight < W_avg){
  144. 			fprintf(out, "%s\n", a[i].name);
  145. 		}
  146. 	}
  147.  
  148.     fclose(in);                                  
  149. 	fclose(out); 
  150.  
  151. 	free(a);
  152.  
  153. 	system("pause");
  154. 	return 0;
  155. }
  156.  
  157.  
  158. 	}
  159. 	}
  160.  
  161.     fclose(in);                                  
  162. 	fclose(out); 
  163.  
  164. 	free(a);
  165.  
  166. 	system("pause");
  167. 	return 0;
  168. }
  169.  
  170.  
  171.  
Success #stdin #stdout 0s 5272KB
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Input file:�r?v�open input file failed!
https://ideone.com/W6QLVo
language:
C (gcc 8.3)
created:
11 days ago
visibility:
public

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