C++ 删除字符串的2种方法小结

#include<iostream>
#include <string>
using namespace std; 
void deletestr(const char *str, const char* sub_str, char *result); 
int main()
{ 
 char str[100],sub[100];
 cin>>str;
 cin>>sub;
 char result;
 deletestr(str,sub,&result);
 return 0;
}
 
void deletestr(const char *str, const char* sub_str, char *result)
{ 
 int sublen = 0;  //获得子串的长度
 const char *t = sub_str;
 while(*t++ != '\0')
 {
 sublen++;
 }
 
 int pos = 0;
 int pp = 0;
 int repos = 0; // 结果子串的索引
 while(*(str + pos) != '\0')
 {
 char t = *(str + pos);
 if(t == *(sub_str + pp)) // 重复子串起始位置
 {
  *(result + repos) = t;
  repos++;
 
  if(pp < sublen - 1) // 还未完全重复
  {
  pp++;
  }
  else if(pp == sublen - 1) // 完全重复了
  {
  pp = 0;
  repos -= sublen; // 回溯下标位置
  }  
 }
 else{ // 不是一样的字符
  *(result + repos) = t;
  repos++;
 }
 pos++;
 }
 *(result + repos) = '\0';
 cout<<result<<endl;
}

#include<iostream>
#include <string>
using namespace std;
 
void deletesub(string &str,const string &sub,int n);
int main()
{ 
 string str,sub;
 cin>>str;
 cin>>sub;
 int n=sub.size();
 deletesub(str,sub,n);
 return 0;
}
void deletesub(string &str,const string &sub,int n)
{
 int m,flag=0,num=0;  //num是子串出现的次数
 while(flag==0)
 {
 m=str.find(sub);
 if(m<0)
  flag=1;
 else
 {
  str.erase(m,n);  //删除子串
  num++;
 }
 }
// cout<<num<<endl;  //子串出现的次数
 cout<<str<<endl;  // 输出删除后的字符串 
}

#include<iostream>
#include<string>
using namespace std;
int main() 
{
	string str;
	str = "123456";
	cout << str << endl;
 
	//方法一：使用substr()
	str = str.substr(0, str.length() - 1);
	cout << str << endl;
 
	//方法二：使用erase()
	str.erase(str.end() - 1);
	cout << str << endl;
 
	//方法三：使用pop_back()
	str.pop_back();
	cout << str << endl;
	return 0;
}