atoi和itoa字符串和数字互相转换函数

字符串转数字(num=num*10+str[i]-‘0’)
num=atoi(str)

#include
using namespace std;
int main()
{
    int num;
    char str[233];
    cin >> str;
    num=atoi(str);
    cout << num << endl;
    return 0;
}

数字转字符串
while(num)
{
str[t++]=num%10+‘0’;
num/=10;
}
ito
a(num,str,进制)

#include
using namespace std;
int main()
{
    int num;
    char str[233];
    cin >> num;
    itoa(num,str,10);
    cout << str <<endl;
        return 0;
}