《c程序设计语言》读书笔记-5.6-指针重写getline等函数

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <curses.h>

int getline_(char *s,int n)
{
char c;
char *sta = s;

while(--n > 0 && (c = getchar()) != EOF && c != '\n')
{
*s++ = c;
}
if(c == '\n')
*s++ = c;
*s = '\0';
return s - sta;
}

int atoi_(char *s)
{
int n,sign;

for(;isspace(*s);s++)
;
sign = (*s == '-') ? -1 : 1;
if(*s == '+' || *s == '-')
s++;
for(n = 0;isdigit(*s);s++)
n = 10 * n + *s - '0';

return sign * n;
}

void reverse_(char *s)
{
int temp;
char *t;

for(t = s + strlen(s) - 1;s < t;s++,t--)
{
temp = *s;
*s = *t;
*t = temp;
}
}

void itoa_(int n,char *s)
{
int sign;
char *t = s;

if((sign = n) < 0)
n = -n;
do
{
*s++ = n % 10 + '0';
}while((n /= 10) != 0);

if(sign < 0)
*s++ ='-';
*s = '\0';
reverse_(t);

}

int strindex_(char *s,char *t)   //返回最右边出现的位置
{
char *sta = s;
char *p,*r;
int n = -2;

for(;*s != '\0';s++)
{
for(p = s,r = t;*r != '\0' && *p == *r;p++,r++)
;
if(r > t && *r == '\0')
n =  s - sta;
}
if(n != -2)
return n;
else
return -1;
}

int main()
{
char p[] = "abcdefgab",q[] = "uh";
int n;
n = strindex_(p,q);

printf("%d",n);

return 0;

}