C++ STL中的basic_string c_str函数

basic_string :: c_str()是C++中的内置函数，它返回一个指向数组的指针，该数组包含一个以null终止的字符序列，这些字符代表了basic_string对象的当前值。此数组包含组成basic_string对象值的相同字符序列，最后还有一个额外的终止空字符。

句法：

const CharT* c_str() const

参数：该函数不接受任何参数。

返回值：该函数返回一个以Null终止的常量指针，该指针指向字符串的字符数组存储。

下面是上述函数的实现：

程序1：

// C++ code for illustration of
// basic_string::c_str function
#include 
#include 
using namespace std;
  
int main()
{
    // declare a example string
    string s1 = "GeeksForGeeks";
  
    // check if the size of the string is same as the
    // size of character pointer given by c_str
    if (s1.size() == strlen(s1.c_str())) {
        cout << "s1.size is equal to strlen(s1.c_str()) " << endl;
    }
    else {
        cout << "s1.size is not equal to strlen(s1.c_str())" << endl;
    }
  
    // print the string
    printf("%s \n", s1.c_str());
}

输出：

s1.size is equal to strlen(s1.c_str()) 
GeeksForGeeks 

程式2：

// C++ code for illustration of
// basic_string::c_str function
#include 
#include 
using namespace std;
  
int main()
{
    // declare a example string
    string s1 = "Aditya";
  
    // print the characters of the string
    for (int i = 0; i < s1.length(); i++) {
        cout << "The " << i + 1 << "th character of string " << s1
             << " is " << s1.c_str()[i] << endl;
    }
}

输出：

The 1th character of string Aditya is A
The 2th character of string Aditya is d
The 3th character of string Aditya is i
The 4th character of string Aditya is t
The 5th character of string Aditya is y
The 6th character of string Aditya is a

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