类型定义

可以用类型定义来建立新的数据类型名。

#include <stdio.h>

typedef int integer;
typedef char *string;

int main(int argc, char const *argv[])
{
    integer i = 233;
    printf("%d\n", i);
    string str = "Hello World!";
    printf("%s\n", str);
    return 0;
}

也可以与结构定义结合使用。

#include <stdio.h>
#include <stdlib.h>

struct node
{
    int data;
    struct node *left;
    struct node *right;
};

typedef struct node n;

int main(int argc, char const *argv[])
{
    n *rootNode = (n *)malloc(sizeof(n));
    n *leftNode = (n *)malloc(sizeof(n));
    n *rightNode = (n *)malloc(sizeof(n));
    rootNode->data = 1;
    rootNode->left = leftNode;
    rootNode->right = rightNode;
    leftNode->data = 2;
    leftNode->left = NULL;
    leftNode->right = NULL;
    rightNode->data = 3;
    rightNode->left = NULL;
    rightNode->right = NULL;
    printf("root: %d.\n", rootNode->data);
    printf("left: %d.\n", rootNode->left->data);
    printf("right: %d.\n", rootNode->right->data);
    free(rootNode);
    free(leftNode);
    free(rightNode);
    return 0;
}