将字符串S1中任何与字符串S2中匹配的字符都删除，实现函数squeeze(s1,s2).

/* test driver */

#include <stdio.h>
#include <string.h>
#include<windows.h>

void squeeze2(char s1[], char s2[]);

//定义buffer的原因是想输出的能够看一下前后元素变化。
int main(void)
{
char *leftstr[] =   //指针数组，它的一个数组元素为一个指针指向一个字符串数组的指针
{
"",
"a",
"antidisestablishmentarianism",
"beautifications",
"characteristically",
"deterministically",
"electroencephalography",
"familiarisation",
"gastrointestinal",
"heterogeneousness",
"incomprehensibility",
"justifications",
"knowledgeable",
"lexicographically",
"microarchitectures",
"nondeterministically",
"organizationally",
"phenomenologically",
"quantifications",
"representationally",
"straightforwardness",
"telecommunications",
"uncontrollability",
"vulnerabilities",
"wholeheartedly",
"xylophonically", /* if there is such a word :-) */
"youthfulness",
"zoologically"
};
char *rightstr[] =
{
"",
"a",
"the",
"quick",
"brown",
"dog",
"jumps",
"over",
"lazy",
"fox",
"get",
"rid",
"of",
"windows",
"and",
"install",
"linux"
};

char buffer[32];
size_t numlefts = sizeof leftstr / sizeof leftstr[0];
size_t numrights = sizeof rightstr / sizeof rightstr[0];
size_t left = 0;
size_t right = 0;

for (left = 0; left < numlefts; left++)
{
for (right = 0; right < numrights; right++)
{
strcpy_s(buffer,100, leftstr[left]);

squeeze2(buffer, rightstr[right]);

printf("[%s] - [%s] = [%s]\n", leftstr[left], rightstr[right], buffer);
}
}
system("pause");
return 0;
}

/* squeeze2: delete all characters occurring in s2 from string s1. */

//拷贝技巧：分别比较两个数组中的各个元素，定义三个变量，两个用来遍历两个数组，第三个用来下表引用，拷贝符合要求的内容。
void squeeze2(char s1[], char s2[])
{
int i, j, k;
int instr2 = 0;

for (i = j = 0; s1[i] != '\0'; i++)
{
instr2 = 0;
for (k = 0; s2[k] != '\0' && !instr2; k++)
{
if (s2[k] == s1[i])
{
instr2 = 1;
}
}

if (!instr2)
{
s1[j++] = s1[i];
}
}
s1[j] = '\0';
}