回答編集履歴
1
再訂正
answer
CHANGED
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@@ -55,4 +55,127 @@
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55
55
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}
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56
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}
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}
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58
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```
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59
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60
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反射性等が問題になるという旨指摘がありましたので現在訂正した部分までを下記に記載しておきます
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61
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再訂正
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62
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```java
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63
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64
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import java.util.*;
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65
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66
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class Order{
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67
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public boolean equals(Object o){
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68
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if((o instanceof Food) && (((Food)o).id==this.id) && (((Food)o).name.equals(this.name))){
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69
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return true;
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70
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71
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}
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else if((o instanceof Order) && (o.hashCode()==this.hashCode())){
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73
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return true;
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74
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75
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}
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return false;
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}
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public int hashCode(){
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79
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80
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81
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char[] cA = name.toCharArray();
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82
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83
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int ch=0;
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84
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85
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for(char t:cA){
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86
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int g=(int)t;
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87
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88
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89
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ch+=g;
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90
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91
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}
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92
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93
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94
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return id*1000+ch;
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95
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96
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}
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97
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98
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public int id;
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public String name;
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100
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public Order(int id,String name){
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101
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this.id = id;
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102
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this.name = name;
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103
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}
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104
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}
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105
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class Food{
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106
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107
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108
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public int hashCode(){
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109
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110
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111
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char[] cA = name.toCharArray();
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112
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113
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int ch=0;
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114
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115
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for(char t:cA){
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116
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117
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int g=(int)t;
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118
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ch+=g;
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119
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120
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}
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121
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122
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123
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return id*1000+ch;
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124
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125
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}
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126
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127
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128
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129
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public int id;
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130
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public String name;
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131
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public Food(int id,String name){
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132
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this.id = id;
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133
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this.name = name;
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134
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}
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135
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}
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136
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137
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public class App {
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138
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public static void main(String[] args) {
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139
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140
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List<Order> orderList = new ArrayList<>();
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141
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List<Food> foodList = new ArrayList<>();
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142
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143
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orderList.add(new Order(1,"アップル"));
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144
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orderList.add(new Order(2, "バナナ"));
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145
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orderList.add(new Order(3, "綿菓子"));
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146
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147
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foodList.add(new Food(1,"アップル"));
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148
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foodList.add(new Food(2, "バナナ"));
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149
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for (int i2 = 0; i2 < orderList.size(); i2++) {
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150
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151
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//比較してくれない
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152
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if(!(foodList.contains(orderList.get(i2)))){
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153
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System.out.println(orderList.get(i2).name);
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154
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}
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155
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156
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157
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158
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}
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159
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Order o = new Order(1, "アップル");
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160
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Food f = new Food(1, "アップル");
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161
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System.out.println(o.hashCode() +" :" + f.hashCode());
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162
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System.out.println("o.equals(o) = " + o.equals(o));
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163
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164
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System.out.println("f.equals(o) = " + f.equals(o));
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165
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System.out.println("o.equals(f) = " + o.equals(f));
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166
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167
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System.out.println("o.hashCode() = " + o.hashCode());
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168
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System.out.println("f.hashCode() = " + f.hashCode());
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169
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Order o2 = new Order(1, "アップル");
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170
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Order p2 = new Order(1, "パップル");
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171
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172
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Food f2 = new Food(1, "アップル");
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173
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System.out.println(p2.hashCode()+" :" +o2.hashCode()+" :" +f2.hashCode());
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174
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System.out.println("p2.equals(o2) = " + p2.equals(o2));
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175
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System.out.println("o2.equals(f2) = " + o2.equals(f2));
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176
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System.out.println("p2.equals(f2) = " + p2.equals(f2));
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177
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+
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178
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+
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179
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+
}
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180
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+
}
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58
181
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```
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