83 lines
2.0 KiB
C
83 lines
2.0 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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// 动态分配内存以存储替换后的字符串
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char* replaceSubstring(const char *str, const char *oldSubstr, const char *newSubstr) {
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int strLen = strlen(str);
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int oldLen = strlen(oldSubstr);
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int newLen = strlen(newSubstr);
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int count=0, i, j, k;
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char *result, *p;
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/**********Program**********/
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//动态内存分配数组空间
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result = (char *)malloc(10000);
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p = result;//将数组首地址赋值给一个指针变量用来操作数组
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for(i=0;i<strLen;i++){//主串的下标遍历
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j = 0;//子串的下标遍历
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//判断当前是否找到和主串中是否和子串开头的字符
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if(oldSubstr[j] != str[i]){
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*p++=str[i];//直接存到新字符串
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continue;
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}
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while(oldSubstr[j] != '\0' && oldSubstr[j++] == str[i++]);
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//如果找到和子串相同的元素
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//则一一比较 一直比较到子串到结束符或者到字符不相等
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if(oldSubstr[j] == '\0'){
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//k为主串中子串的起始位置
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k=0;
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while(newSubstr[k] != '\0'){
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*p++ = newSubstr[k++];
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}
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i--;
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}else{//只是前面几个字符匹配 后续并不匹配 则需要从头开始存
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i-=j;
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*p++=str[i];
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}
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}
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*p='\0';
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/*
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字符串：abcabc
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需要替换的子串：a
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替换后的子串：##
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示例输出：##bc##bc
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*/
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/********** End **********/
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return result;
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}
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int main() {
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char str[10000];
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char oldSubstr[100];
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char newSubstr[100];
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char *replacedStr;
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// 获取用户输入
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printf("【请输入原字符串：】");
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fgets(str, sizeof(str), stdin);
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str[strcspn(str, "\n")] = 0; // 去除换行符
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printf("【请输入要替换的子串：】");
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fgets(oldSubstr, sizeof(oldSubstr), stdin);
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oldSubstr[strcspn(oldSubstr, "\n")] = 0; // 去除换行符
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if (strstr(str, oldSubstr) == NULL) {
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printf("原字符串不包含所输入的子串。\n");
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return 0;
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}
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printf("【请输入替换后的子串：】");
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fgets(newSubstr, sizeof(newSubstr), stdin);
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newSubstr[strcspn(newSubstr, "\n")] = 0; // 去除换行符
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replacedStr = replaceSubstring(str, oldSubstr, newSubstr);
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printf("【示例输出：】%s\n", replacedStr);
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// 释放动态分配的内存
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free(replacedStr);
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return 0;
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}
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