How do you define strings in the C programming language?

In the C programming language, strings can be defined using character arrays. Specifically, the method is:

1. Define a string using a character array.

char str[100]; // 定义一个长度为100的字符数组来存储字符串

1. Define a string and allocate memory space using pointers.

char *str;
str = (char *)malloc(100 * sizeof(char)); // 动态分配100个字符的内存空间

It is important to consider the length of a string when defining it to ensure that the allocated memory space is enough to store the string and prevent memory overflow. Additionally, when defining a string using pointers, one should use dynamic memory allocation functions like malloc to allocate memory space and manually free the memory after use (using the free function).