C语言实现字符串替换

青旅半醒 2022-03-15 18:06 844阅读 0赞

**关键点：**  
1.注意字符数组与字符串的区别；在字符数组最后一个字符后面加上’\\0’就构成了一个字符串。

/*-------------------------------------------------
    功能：实现字符串的替换
    描述：第一行输入原字符串，第二行输入要替换字符串，
    第三行输入新的字符串
    输入示例：
    There is an orange, do you want to eat it?
    orange
    apple
    输出示例：
    There is an apple, do you want to eat it?
    Author: Zhang Kaizhou
    Date: 2019-8-9 11:11:32
    --------------------------------------------------*/
    
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #define MAXSIZE 300
    
    void str_replace(char * str1, char * str2, char * str3);
    
    int main(){
        char str1[MAXSIZE];
        char str2[MAXSIZE];
        char str3[MAXSIZE];
        gets(str1);
        gets(str2);
        gets(str3);
        str_replace(str1, str2, str3);
        puts(str1);
    
        return 0;
    }
    
    void str_replace(char * str1, char * str2, char * str3){
        int i, j, k, done, count = 0, gap = 0;
        char temp[MAXSIZE];
        for(i = 0; i < strlen(str1); i += gap){
            if(str1[i] == str2[0]){
                done = 0;
                for(j = i, k = 0; k < strlen(str2); j++, k++){
                    if(str1[j] != str2[k]){
                        done = 1;
                        gap = k;
                        break;
                    }
                }
                if(done == 0){ // 已找到待替换字符串并替换
                    for(j = i + strlen(str2), k = 0; j < strlen(str1); j++, k++){ // 保存原字符串中剩余的字符
                        temp[k] = str1[j];
                    }
                    temp[k] = '\0'; // 将字符数组变成字符串
                    for(j = i, k = 0; k < strlen(str3); j++, k++){ // 字符串替换
                        str1[j] = str3[k];
                        count++;
                    }
                    for(k = 0; k < strlen(temp); j++, k++){ // 剩余字符串回接
                        str1[j] = temp[k];
                    }
                    str1[j] = '\0'; // 将字符数组变成字符串
                    gap = strlen(str2);
                }
            }else{
                gap = 1;
            }
        }
        if(count == 0){
            printf("Can't find the replaced string!\n");
        }
        return;
    }