char ch[500];
int i;
gets(ch);
for(i=0;i<strlen(ch);i++)
{
    printf("%c",ch[i]^0x20);
}
回ls,位运算法

OX20是什么东西？```

对了，真正使用的使用先len=strlen(ch),然后条件变为<len,否则速度体现不出来

一个数

0x20 = 32
ps: 终于下好了.....

#include<stdio.h>
#include<string.h>
int main()
{
    int i,len;
    char ch[500];
    for(gets(ch),i=0,len=strlen(ch);i<len;i++) ch[i]^=0x20; puts(ch);
    return 0;
}

明白``谢谢``

拿个100万的数据比较下应该能看出效率差
ps:这个可以实现大小写互逆转换

效率差的不算大............

#include<stdio.h>
#include<string.h>
int main(void)
{
    int x[520000],i,len;
    gets((char *)x); len=(strlen((char *)x)>>2)+1;
    for(i=0;i<len;++i)
    {
        x[i]^=0x20202020;
    }
    puts((char *)x);
    return 0;
}        

Name: "S.K" Problem ID "3"
Submit Time: 2008/5/30-22:28

G++: Compile OK

Test 1:    Accepted    Time = 0 ms
Test 2:    Accepted    Time = 141 ms
Test 3:    Accepted    Time = 121 ms
────────────────
Problem ID     3
Test Result    Accepted
Total Time     262 ms
Total Memory   2064 Kb
Code Length    249 Bytes

#include<stdio.h>
#include<string.h>
int main()
{
    int i,len;
    char ch[2000001];
    gets(ch);
    len=strlen(ch);
    for(i=0;i<len;i++)
    {
        if(ch[i]>='a')
            ch[i]-=32;
        else
            ch[i]+=32;
    }    
    puts(ch);
    return 0;
}

Name: "S.K" Problem ID "3"
Submit Time: 2008/5/30-22:30

G++: Compile OK

Test 1:    Accepted    Time = 0 ms
Test 2:    Accepted    Time = 191 ms
Test 3:    Accepted    Time = 181 ms
────────────────
Problem ID     3
Test Result    Accepted
Total Time     372 ms
Total Memory   1984 Kb
Code Length    290 Bytes

#include<stdio.h>
#include<string.h>
int main(void)
{
    char x[2000001]; int i,len;
    gets(x); len=strlen(x);
    for(i=0;i<len;++i)
    {
        x[i]^=0x20;
    }
    puts(x);
    return 0;
}        

Name: "S.K" Problem ID "3"
Submit Time: 2008/5/30-22:31

G++: Compile OK

Test 1:    Accepted    Time = 0 ms
Test 2:    Accepted    Time = 131 ms
Test 3:    Accepted    Time = 161 ms
────────────────
Problem ID     3
Test Result    Accepted
Total Time     292 ms
Total Memory   1984 Kb
Code Length    221 Bytes

0x20=32 怎么算的啊,请教.