the c programming language 习题 第二章

exercise2.4
void squeeze(char s[],char t[])
{
int i,j,k;
int lens,lent;
lens=strlen(s);
lent=strlen(t);
for(i=0,k=0;i<lens;i++)
{
for(j=0;j<lent;j++)
if(s[i]==t[j])
break;
if(j==lent)
s[k++]=s[i];
}
s[k]='\0';
} 
exercise2.5
int any(char s[],char t[])
{
int i,j;
for(i=0;s[i]!='\0';i++)
for(j=0;t[j]!='\0';j++)
if(s[i]==t[j])
return i;
return -1;
} 
exercise2.9
int bitcount(unsigned x)
{
int b;
b=0;
while(x)
{
x&=(x-1);
b++;
}
return b;
} 
exercise2.10
int lower(int c)
{
return (c>='A'&&c<='Z')?c+'a'-'A':c;
}