过滤多余的空格

#include <stdio.h>
#include <string.h>
char *process(char * s);
int main(void)
{
    char str[200];
    //char str[200] = "Hello      world.This is    c language.";
    char *s;
    
    gets(str);
    s = process(str);
    puts(s);
    
    return 0;
}
char *process(char *s)
{
    char str_t[200];
    char *p1, *p2;
    
    strcpy(str_t, s);   //复制原字符串
    p1 = str_t;         //指向临时字符串的指针
    p2 = s;             //指向原来字符串的指针
    
    while (*p1) {
        if (*p1 != ' ') {
            *p2 = *p1;
            p1++;
            p2++;
        } else {
            *p2 = ' ';
            p1++;
            p2++;
            while (*p1 == ' ') {
                p1++;
            }
        }
    }
    *p2 = '';
    
    return s;
}

参考老师的讲解，思考后重新编写。

#include <stdio.h>

void process(char *s1, char *s2);
int main(void)
{
    //char str1[201];     //str1是一个指向数组第一个元素的常量指针
    char str1[200] = "Hello      world.This is    c language.";
    char str2[201];
    
    //gets(str1);
    process(str1, str2);
    puts(str2);
    
    return 0;
}
//s1 = str1; s2 = str2
void process(char *s1, char *s2)
{
    char *p1, *p2;
    
    p1 = s1;
    p2 = s2;
    
    while (*p1) {
        if (*p1 != ' ') {
            *p2 = *p1;
            p1++;
            p2++;
        } else {
            //循环后，p1指向后面第一个不是空格的元素
            while (*p1 == ' ') {
                p1++;
            }
            *p2 = ' ';
            p2++;
        }
    }
    *p2 = '';
}