//atoi的实现

复制代码 代码如下:

#include<iostream>

using namespace std;

int atio1(char *s)

{

int sign=1,num=0;

if(*s=='-')

sign=-1;

s++;

while((*s)!='')

{

num=num*10+(*s-'0');

s++;

}

return num*sign;

}

//itoa的实现

复制代码 代码如下:

char *itoa(int num, char *str, int radix)

{

char* ptr = str;

int i;

int j;

while (num)

{

*ptr++ = string[num % radix];

num /= radix;

if (num < radix)

{

*ptr++ = string[num];

*ptr = '';

break;

}

}

j = ptr - str - 1;

for (i = 0; i < (ptr - str) / 2; i++)

{

int temp = str[i];

str[i] = str[j];

str[j--] = temp;

}

return str;

}

复制代码 代码如下:

int main()

{

char *s="-123567890";

cout<<atio1(s);

system("pause");

}