《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;

}

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《c程序设计语言》读书笔记-5.6-指针重写getline等函数

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