1、利用C語言實現字元型陣列轉換成整形，其中需要考慮到很多邊界條件，其實現程式碼如下：

#include<stdio.h>
#include<limits.h>//標頭檔案定義最大最小的整形
#include<iostream>//包含system函式
using namespace std;
int StrToInt(const char* str)//字元型陣列轉換成整形
{
	if (str == NULL || *str == '\0')
	{
		return 0;
	}	
	long long num = 0;
	int sign = 1;
	while (*str == ' ')//遇到空格就跳過
	{
		str++;
	}
	if (*str == '+')//遇到‘+’表示是整數
	{
		str++;
	}
	else if (*str == '-')//遇到‘-’表示是負數
	{
		str++;
		sign = -1;
	}
	while (*str != '\0')
	{
		if (*str >= '0'&&*str <= '9')
		{
			num = num * 10 + (*str - '0')*sign;
			if (num >= INT_MAX)
			{
				return INT_MAX;
			}
			else if (num <= INT_MIN)
			{
				return INT_MIN;
			}
		}
		else
		{
			break;
		}
		str++;
	}
	return (int)num;//注意將返回值轉換為int型
}
int main()
{
	char str1[] = "  +125874";
	char str2[] = "-789546";
	char str3[] = "4587q";
	char str4[] = "qq456";
	char str5[] = "0";
	char str6[] = "12345678941123456789";
	char str7[] = "  -1245678941253647845612";
	char str8[] = "\0";
	printf("%d\n", StrToInt(str1));
	printf("%d\n", StrToInt(str2));
	printf("%d\n", StrToInt(str3));
	printf("%d\n", StrToInt(str4));
	printf("%d\n", StrToInt(str5));
	printf("%d\n", StrToInt(str6));
	printf("%d\n", StrToInt(str7));
	printf("%d\n", StrToInt(str8));
	system("pause");
	return 0;
}
 

實驗結果如下所示：

2、利用C++實現字串轉整形，其實現程式碼如下，

#include<iostream>
#include<string>
using namespace std;
int StrToInt(string &str)
{
	int len = str.length();
	if (len == 0)
	{
		return 0;
	}
	long long num = 0;
	int sign = 1;
	int i = 0;
	while (str[i] == ' ')
	{
		++i;
	}
	if (str[i] == '-')
	{
		sign = -1;
		++i;
	}
	else if (str[i] == '+')
	{
		++i;
	}
	while (i != len)
	{
		if (str[i] >= '0'&&str[i] <= '9')
		{
			num = num * 10 + (str[i] - '0')*sign;
			if (num >= INT_MAX)
			{
				return INT_MAX;
			}
			else if (num <= INT_MIN)
			{
				return INT_MIN;
			}
			++i;
		}
		else
		{
			break;
		}
	}
	return (int)num;
}
int main()
{
	string str1 = "  +125874";
	string str2 = "-789546";
	string str3 = "4587q";
	string str4 = "qq456";
	string str5 = "0";
	string str6 = "12345678941123456789";
	string str7 = "  -1245678941253647845612";
	string str8 = "-00000004571a";
	cout << StrToInt(str1) << endl;
	cout << StrToInt(str2) << endl;
	cout << StrToInt(str3) << endl;
	cout << StrToInt(str4) << endl;
	cout << StrToInt(str5) << endl;
	cout << StrToInt(str6) << endl;
	cout << StrToInt(str7) << endl;
	cout << StrToInt(str8) << endl;
	system("pause");
	return 0;
}
 

實驗結果如下所示，