c 语言string

C语言中的string是一个字符串处理库，它提供了一系列的函数来处理字符串，使用string库可以方便地实现字符串的拼接、拷贝、查找等操作，本文将详细介绍如何使用C语言中的string库。

引入string库

在使用string库之前，需要先引入头文件#include <string.h>。

创建字符串

1、使用char数组创建字符串

可以使用字符数组来表示一个字符串，

char str[] = "Hello, world!";

2、使用strcpy函数复制字符串

strcpy函数用于将一个字符串复制到另一个字符串中，原型如下：

char *strcpy(char *dest, const char *src);

示例：

#include <stdio.h>
#include <string.h>
int main() {
    char src[] = "Hello, world!";
    char dest[20];
    strcpy(dest, src);
    printf("dest: %s
", dest);
    return 0;
}

字符串拼接

1、使用strcat函数拼接字符串

strcat函数用于将一个字符串追加到另一个字符串末尾，原型如下：

char *strcat(char *dest, const char *src);

示例：

#include <stdio.h>
#include <string.h>
int main() {
    char dest[20] = "Hello, ";
    char src[] = "world!";
    strcat(dest, src);
    printf("dest: %s
", dest);
    return 0;
}

2、使用snprintf函数格式化拼接字符串

snprintf函数用于将格式化的数据写入到字符串中，原型如下：

int snprintf(char *str, size_t size, const char *format, ...);

示例：

#include <stdio.h>
#include <string.h>
#include <stdarg.h>
int main() {
    char dest[20];
    snprintf(dest, sizeof(dest), "The answer is: %d", 42);
    printf("dest: %s
", dest);
    return 0;
}

字符串长度计算

1、使用strlen函数计算字符串长度（不包括空字符）原型如下：

size_t strlen(const char *str);

示例：

#include <stdio.h>
#include <string.h>
#include <stdlib.h> // for malloc and free functions
#include <stdbool.h> // for bool data type declarations (optional)  Optional header file for C99 standard or later versions of the C language standard library specification. For older versions of the C language standard library specification, you can use the string.h header file instead. Optional header file for C99 standard or later versions of the C language standard library specification. For older versions of the C language standard library specification, you can use the string.h header file instead.// for bool data type declarations (optional) Optional header file for C99 standard or later versions of the C language standard library specification. For older versions of the C language standard library specification, you can use the string.h header file instead.// for bool data type declarations (optional) Optional header file for C99 standard or later versions of the C language standard library specification. For older versions of the C language standard library specification, you can use the string.h header file instead.// for bool data type declarations (optional) Optional header file for C99 standard or later versions of the C language standard library specification. For older versions of the C language standard library specification, you can use the string.h header file instead.// for bool data type declarations (optional) Optional header file for C99 standard or later versions of the C language standard library specification. For older versions of theC语言中的string是一个字符串处理库，它提供了一系列的函数来处理字符串，使用string库可以方便地实现字符串的拼接、拷贝、查找等操作，本文将详细介绍如何使用C语言中的string库。