c语言 11-8

1、

#include <stdio.h>

void del_num(char *s)  //函数的形参为指针，也就是字符串数组的数组名，相当于指向数组第一个元素的指针。 
{
    char *tmp = s;  // 将指针tmp赋值为指针s，即指向传入的字符串数组的第一个元素的指针 
    while(*tmp)  //循环条件为指针tmp指向的元素，如果tmp指针指向的元素不为null则执行循环体 
    {
        if(*tmp >= '0' && *tmp <= '9')
            tmp++;   //当指针tmp指向的元素为数字时，指针tmp后移 
        else
            *s++ = *tmp++;  //当指针tmp指向的元素不是数字时，将tmp指向的元素赋值给指针s指向的元素，同时指针s和指针tmp后移 
    }
    *s = ''; //指针tmp指向null是循环终止，如果*tmp最后一个是非数字字符或者数字时，并没有将最后的null赋值给*s，因此需要将null赋值给*s，使其形成字符串。此时指针s指向字符串的最后
    //一个字符 
}

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

2、

#include <stdio.h>

void del_num(char *s)
{
    char *tmp = s;
    while(*tmp)
    {
        if(*tmp < '0' || *tmp > '9')
            *s++ = *tmp++;
        else
            tmp++;
    }
    *s = '';
}

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

3、

#include <stdio.h>

void del_num(char *s)
{
    int j = 0;
    char *tmp = s;
    while(*tmp)
    {
        if(*tmp >= '0' && *tmp <= '9')
            tmp++;
        else
        {
            *s++ = *tmp++;
            j++;
        }
    }
    *s = '';
    
    while(j--)
        s--;
    
    printf("result: after deletion: %s
", s);
}

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

4、

#include <stdio.h>


char *del(char *s1, char *s2)
{
    char *tmp = s2;
    while(*s1)
    {
        if(*s1 < '0' || *s1 > '9')
            *s2++ = *s1++;
        else
            s1++;
    }
    *s2 = '';
    return tmp;
}

int main(void)
{
    char str1[128];
    char str2[128];
    printf("str1: "); scanf("%s", str1);
    
    printf("result:  %s
", del(str1, str2));
    return 0;
}

5、

#include <stdio.h>

char *del(char *s)
{
    char *t = s;
    char *tmp = s;
    while(*tmp)
    {
        if(*tmp < '0' || *tmp > '9')
            *s++ = *tmp++;
        else
            tmp++;
    }
    *s = '';
    return t;
}

int main(void)
{
    char str[128];
    printf("str: "); scanf("%s", str);
    
    printf("result after deleting numbers: %s
", del(str));
    return 0;
}

6、

#include <stdio.h>

char *del(char *s1, char *s2)
{
    char *t = s2;
    while(*s1)
    {
        if(*s1 < '0' || *s1 > '9')
            *s2++ = *s1;
        s1++;    
    }
    return t;
} 

int main(void)
{
    char str1[128];
    char str2[128];
    printf("str1: "); scanf("%s", str1);
    
    printf("result after deleting numbers: %s
", del(str1, str2));
    return 0;
}

7、

#include <stdio.h>

char *del(char *s1)
{
    char tmp[128];
    char *t = tmp;
    char *z = tmp;
    while(*s1)
    {
        if(*s1 < '0' || *s1 > '9')
            *t++ = *s1;
        s1++;
    }
    *t = '';
    return z;
}

int main(void)
{
    char str[128];
    printf("str: "); scanf("%s", str);
    
    printf("result after deleting numbers: %s
", del(str));
    return 0;
}