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

参考： C ++ atoi()函数

翻译自: https://www.includehelp.com/cpp-tutorial/atoi-function-with-example.aspx

c ++atoi函数