《c程序设计语言》读书笔记-字符型0-9转为数字0-9

#include <stdio.h>

#define Num 10

int atoi(char s[]);

int main()
{
    int c,i = 0;
    char s[Num];
    int result;

    while((c = getchar()) != EOF && c != '\n' && i < Num)
    {
        s[i] = c;
        i++;
    }
    result = atoi(s);
        printf("%d\n",result);

        return 0;
}
int atoi(char s[])
{
    int i,n = 0;

    for(i = 0;s[i] >= '0' && s[i] <= '9';i++)
    {
        n = 10*n + (s[i] - '0');
    }

     return n;
}