建造者模式-C语言实现

UML类图：

代码实现：

#include <stdio.h>
#include <stdlib.h>// 产品类
typedef struct {char* part1;char* part2;char* part3;
} Product;// 抽象建造者类
typedef struct {void (*buildPart1)(void*, const char*);void (*buildPart2)(void*, const char*);void (*buildPart3)(void*, const char*);Product* (*getResult)(void*);
} Builder;// 具体建造者类
typedef struct {Product* product;void (*buildPart1)(void*, const char*);void (*buildPart2)(void*, const char*);void (*buildPart3)(void*, const char*);Product* (*getResult)(void*);
} ConcreteBuilder;void ConcreteBuilder_buildPart1(void* obj, const char* value) {ConcreteBuilder* builder = (ConcreteBuilder*)obj;builder->product->part1 = malloc(sizeof(char) * (strlen(value) + 1));strcpy(builder->product->part1, value);
}void ConcreteBuilder_buildPart2(void* obj, const char* value) {ConcreteBuilder* builder = (ConcreteBuilder*)obj;builder->product->part2 = malloc(sizeof(char) * (strlen(value) + 1));strcpy(builder->product->part2, value);
}void ConcreteBuilder_buildPart3(void* obj, const char* value) {ConcreteBuilder* builder = (ConcreteBuilder*)obj;builder->product->part3 = malloc(sizeof(char) * (strlen(value) + 1));strcpy(builder->product->part3, value);
}Product* ConcreteBuilder_getResult(void* obj) {ConcreteBuilder* builder = (ConcreteBuilder*)obj;return builder->product;
}// 指挥者类
typedef struct {void (*construct)(void*, Builder*);
} Director;void Director_construct(void* obj, Builder* builder) {Director* director = (Director*)obj;director->builder = builder;director->builder->buildPart1(director->builder, "Part 1");director->builder->buildPart2(director->builder, "Part 2");director->builder->buildPart3(director->builder, "Part 3");
}int main() {ConcreteBuilder builder;Product* product;builder.product = malloc(sizeof(Product));builder.buildPart1 = ConcreteBuilder_buildPart1;builder.buildPart2 = ConcreteBuilder_buildPart2;builder.buildPart3 = ConcreteBuilder_buildPart3;builder.getResult = ConcreteBuilder_getResult;Director director;director.construct = Director_construct;director.construct(&director, (Builder*)&builder);product = builder.getResult(&builder);printf("Part 1: %s\n", product->part1);printf("Part 2: %s\n", product->part2);printf("Part 3: %s\n", product->part3);free(product->part1);free(product->part2);free(product->part3);free(product);return 0;
}

在上面的示例代码中，首先定义了产品类Product，其中包含了三个部分。然后定义了抽象建造者类Builder，其中包含了构建产品的各个部分的函数指针。

接着定义了具体建造者类ConcreteBuilder，它实现了抽象建造者类中的函数，并拥有一个指向产品对象的指针。具体建造者类通过实现不同的构建方法来构建产品的不同部分，并提供获取最终产品的函数。

最后定义了指挥者类Director，它接收一个具体建造者对象作为参数，通过调用具体建造者的函数来构建产品。

在main函数中，创建了具体建造者对象builder和指挥者对象director，然后通过指挥者对象来构建产品。最后获取并打印产品的各个部分。

建造者模式将产品的构建过程与产品的表示分离，使得构建过程可以独立于产品而变化。通过使用建造者模式，可以更加灵活地构建复杂对象，并且可以复用相同的构建过程来创建不同的产品。