c ++atoi函数_atoi（）函数以及C ++中的示例

小灰灰 2023-03-05 12:44 6阅读 0赞

c ++atoi函数

## C ++ atoi()函数 **(**C++ atoi() function**)** ##

**atoi() function** is a library function of **cstdlib** header. It is used to convert the given string value to the integer value. It accepts a string containing an integer (integral) number and returns its integer value.

**atoi()函数**是**cstdlib**标头的库函数。 它用于将给定的字符串值转换为整数值。 它接受包含整数(整数)的字符串，并返回其整数值。

**Syntax of atoi() function:**

**atoi()函数的语法：**

C++11:

C ++ 11：

int atoi (const char * str);

**Parameter(s):**

**参数：**

*  str – represents a string containing an integer (integral) number.
    
    str –表示包含整数(整数)的字符串。

**Return value:**

**返回值：**

The return type of this function is int, it returns the integer converted value.

该函数的返回类型为int ，它返回整数转换后的值。

**Example:**

**例：**

Input:
        str = "123";
    
        Function call:
        atoi(str);
    
        Output:
        123

### C ++代码演示atoi()函数的示例 **(**C++ code to demonstrate the example of atoi() function**)** ###

// C++ code to demonstrate the example of
    // atoi() function
    
    #include <iostream>
    #include <cstdlib>
    #include <string.h>
    using namespace std;
    
    // main() section
    int main()
    {
        char str[50];
    
        strcpy(str, "123");
        cout << "atoi(\"" << str << "\"): " << atoi(str) << endl;
    
        strcpy(str, "-123");
        cout << "atoi(\"" << str << "\"): " << atoi(str) << endl;
    
        strcpy(str, "0");
        cout << "atoi(\"" << str << "\"): " << atoi(str) << endl;
    
        strcpy(str, "1234567");
        cout << "atoi(\"" << str << "\"): " << atoi(str) << endl;
    
        strcpy(str, "12345678");
        cout << "atoi(\"" << str << "\"): " << atoi(str) << endl;
    
        strcpy(str, "-12345678");
        cout << "atoi(\"" << str << "\"): " << atoi(str) << endl;
    
        return 0;
    }

**Output**

**输出量**

atoi("123"): 123
    atoi("-123"): -123
    atoi("0"): 0
    atoi("1234567"): 1234567
    atoi("12345678"): 12345678
    atoi("-12345678"): -12345678

Reference: [C++ atoi() function][C_ atoi_ function]

参考： [C ++ atoi()函数][C_ atoi_ function]

> 翻译自: [https://www.includehelp.com/cpp-tutorial/atoi-function-with-example.aspx][https_www.includehelp.com_cpp-tutorial_atoi-function-with-example.aspx]

c ++atoi函数

[C_ atoi_ function]: http://www.cplusplus.com/reference/cstdlib/atoi/
[https_www.includehelp.com_cpp-tutorial_atoi-function-with-example.aspx]: https://www.includehelp.com/cpp-tutorial/atoi-function-with-example.aspx