转载 让指针不再困扰你
声明：moonwalker 作于2008年4月26日 转载请注明出处 指针对一部分初学者来说一直是一个无法逾越的障碍，没有指针的C语言就好像没有左腿的短跑运动员。今天我来试试换一种方法来理解指针，希望能帮还在为指针挣扎的朋友们理清思路，高手略过即可。 我们先认为内存是一家客栈（看起来这和老掉牙的大楼的比喻没什么区别，但是请你耐心看下去）。同大部分的客栈一样，这家客栈有天、地、人等各种档次的房间，用现在的话就是单人间、双人间、四人间等等。来住店的客人也是车水马龙，三教九流都有，我们看看都有哪些人： 快乐单身汉char，还有char的小弟unsigned char，他们只住...
最简单的指针
将输入的字符串的最后一位变成x，如
input
abcd
output
abcx
---------------
#include <stdio.h>
int main(void)
{
char a[10], *p;
p = a;
scanf("%s",p);
for ( ; *p !='\0' ; p++)
;
p--;
*p = 'X';
printf("%s",a);
getch();
return 0;
}
1.5.1 Word Counting(The wrong version)
#include <stdio.h>
#define OUT 0 /* outside word */
#define IN 1 /* inside word */
int main(void)
{
int c, nw;
nw = 0;
while((c = getchar()) != EOF)
{
while ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
;
+...
求百位 十位 个位数 都不相同的3位数都列出来
#include <stdio.h>
int main(void){ int num, baiwei, shiwei, gewei, i, j; i = j = 0; for (num = 100; num < 999 ; ++num) { baiwei = num / 100; shiwei = (num - baiwei*100) / 10; gewei = num - baiwei*100 - shiwei *10; if ((baiwei != shiwei) && (ba...
Exercise 1-10
/* Write a program to copy its input to its output,replacing each tab by \t, *each backspace by \b,and each backslash by \\ .This makes tabs and backspaces *visible in an unambiguous way */ #include <stdio.h> int main(void) { int c; while ((c = getchar()) != EOF) { if...
Exercise 1-9
/*Write a program to copy its input to its output, *replacing each string of one or more blanks by a single blank*/#include <stdio.h>
#define OUT 1 /* outside the word */#define IN 0 /* inside the word */
int main(void){ int c,state; state = OUT; while ((c = getchar()) != EO...
Exercise 1-8
/* Write a program to count blanks,tabs,and newlines */
#include <stdio.h>
int main(void)
{
int c, nb, nt, nn;
nb = nt = nn = 0;
while((c = getchar()) != EOF)
{
if (c == ' ') ++nb;
if (c == '\t') ++nt;
if (c == '\n') ++nn;
}
print...
1.5.3 Line Counting
/* 1st version */
#include <stdio.h>
int main(void)
{
int c, nl;
nl = 0;
while ((c = getchar()) != EOF)
if (c == '\n')
++nl;
printf("%d",nl);
getch();
return 0;
}
===========================
/* 2nd version */
#include <stdio.h...
1.5.2 Character Counting
/* 1st version */
#include<stdio.h>
int main(void)
{
int c, nc;
nc = 0;
while((c = getchar()) !=EOF)
{
++nc;
}
printf("%d",nc);
getch();
return 0;
}
======================
/* 2nd version */
#include <stdio.h>
int main(v...
Exercise 1-7
/* Write a program to print the value of EOF */
/* 1st version */
#include <stdio.h>
int main(void){ int c;
c = EOF;
printf("the value of EOF is %d",c);
getch(); return 0;}
===============/* 2nd version */
#include <stdio.h>
int main(void){ printf("...
1.5.1 File Copying
/* 1st verion.copy input to output */
#include <stdio.h>
int main (void){ int c;
c = getchar(); while (c != EOF) { putchar(c); c = getchar(); }
return 0;}
===========================
/* 2ed version.copy input to output */
#include <stdio.h>
...
1.4 Symbolic Constants
/* The version of symbolic constants : print Fahrenheit-celsious table */
#include<stdio.h>
#define LOWER 0#define UPPER 300#define STEP 20
int main(viod){ float fahr;
for (fahr = LOWER; fahr <= UPPER; fahr += STEP ) { printf("%3.0f%6.1f\n", fahr, (5.0/9.0) * ( f...
Exercise 1-5
/* Modify the temperature conversion program to print the table in reverse order, *that is form 300 degrees to 0. */
#include <stdio.h>
int main(void){ float fahr; for(fahr = 300; fahr >= 0; fahr-=20) { printf("%3.0f%6.1f\n",fahr,(5.0/9.0) * (fahr - 32)); } ...
1.3 The for statement
/* the version of for statement;print Fahrenheit - Celsius table */
#include <stdio.h>
int main(void){ float fahr;
for ( fahr = 0; fahr <=300; fahr+=20) { printf("%3.0f%6.1f\n",fahr,(5.0/9.0)*(fahr-32)); } getch(); return 0;}
Exercise 1-4
/* Write a program to print the corresponding Celsius to Fahrenhei table */
#include <stdio.h>
int main(void){ float cels, fahr; int lower, upper, step; lower = 0; upper = 100; step = 10; cels = lower; while ( cels <= upper) { fahr = 9 * cels / 5 + 3...
Exercise 1-3
/* Modify the temperature conversion program to print a heading above the table */
#include <stdio.h>
int main(void){ float fahr, cels; int lower, upper, step; lower = 0 ; upper = 300; step = 20; fahr = lower; printf("F\tC\n"); while (fahr <= upper) { ...
1.2 Variables and Arithmetic Expressions
The program uses the formula [ Celsius = (5/9) * (Fahrenheit - 32)] to print the following table of Fahrenheit temperatures and their centigrade or Celsius equivalents:
=============
/* print Fahrenheit - Celsius table for fahr =0, 20, ..., 300 */
#include <stdio.h>
int main(void)
{
...
1.1 Getting Started
the program to print "hello, world"
==============
#include <stdio.h>
int main(void)
{
printf("hello, world");
return 0;
}
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最新评论
- flamemiracle：很不错哦，简单易懂很形象
- flamemiracle：你这个程序跑不起来的，少了个头文件#include <conio.h>
- 雪洋：天啊，太麻烦了吧?