c语言 9-8

1、

#include <stdio.h>

void put(char x[])
{
    int len = 0;
    while(x[len])
        len++;
    while(len-- > 0)
    {
        putchar(x[len]); 
    }
}

int main(void)
{
    char str[128];
    printf("str: "); scanf("%s", str);
    put(str);
    return 0;
}

2、

#include <stdio.h>

void put(char x[])
{
    int len = 0;
    while(x[len])
        len++;
    int i = 0;
    while(x[i])
    {
        putchar(x[len - 1 - i]);
        i++;
    }
}

int main(void)
{
    char str[128];
    printf("str:  "); scanf("%s", str);
    put(str);
    return 0;
}

3、

#include <stdio.h>

void put(char x[])
{
    int len = 0;
    while(x[len])
        len++;
    char tmp[len];
    int i = 0;
    while(x[i])
    {
        tmp[i] = x[len - 1 - i];
        i++;
    }
    
    for(i = 0; i < len; i++)
    {
        x[i] = tmp[i];
    }
    i = 0;
    while(x[i])
        putchar(x[i++]);
}

int main(void)
{
    char str[128];
    printf("str: "); scanf("%s", str);
    put(str);
    return 0;
}

4、

#include <stdio.h>

void put(char x[])
{
    int len = 0;
    while(x[len])
        len++;
    int i;
    for(i = 0; i < len / 2; i++)
    {
        int tmp = x[i];
        x[i] = x[len - 1 - i];
        x[len - 1 - i] = tmp;
    }
    i = 0;
    while(x[i])
        putchar(x[i++]);
}

int main(void)
{
    char str[128];
    printf("str: "); scanf("%s", str);
    put(str);
    return 0;
}

5、

#include <stdio.h>

void put(char x[])
{
    int len = 0;
    while(1)
    {
        if(x[len] == '')
            break;
        len++;
    }
    char tmp[len];
    int i;
    for(i = 0; i < len; i++)
    {
        tmp[i] = x[len - 1 - i];
        putchar(tmp[i]);
    }
}

int main(void)
{
    char str[128];
    printf("str: "); scanf("%s", str);
    put(str);
    return 0;
}