我有3个字符串变量，用户输入了三个单词
并且该程序必须按字母顺序对它们进行排序(如果我试图用if语句进行排序)，但问题是，如果用户插入的前5个字符是相同的，我就厌倦了每次重复代码的麻烦。
这是我的代码:
#include <iostream>
using namespace std;
int main ()
{
string w1,w2,w3;
cout<<"please enter three words"<<endl;
cin >> w1 >> w2 >> w3;
if(w1[0] == w2[0])
{
if(w1[1] < w2[1] && w1[0] < w3[0]){
cout << w1;
if(w2[0] < w3[0])
{
cout << "\t" << w2 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w2;
}
}else if(w2[1] < w1[1] && w2[0] < w3[0]){
cout << w2;
if(w1[0] < w3[0])
{
cout << "\t" << w1 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w1;
}
}else if(w3[0] < w1[0] && w3[0] < w2[0]){
cout << w3;
if(w1[1] < w2[1])
{
cout << "\t" << w1 <<"\t" << w2;
}
else
{
cout << "\t" << w2<<"\t" << w1;
}
}
}
else if(w2[0] == w3[0])
{
if(w1[0] < w2[0] && w1[0] < w3[0]){
cout << w1;
if(w2[1] < w3[1])
{
cout << "\t" << w2 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w2;
}
}else if(w2[0] < w1[0] && w2[1] < w3[1]){
cout << w2;
if(w1[0] < w3[0])
{
cout << "\t" << w1 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w1;
}
}else if(w3[0] < w1[0] && w3[1] < w2[1]){
cout << w3;
if(w1[0] < w2[0])
{
cout << "\t" << w1 <<"\t" << w2;
}
else
{
cout << "\t" << w2<<"\t" << w1;
}
}
}
else if(w3[0] == w1[0])
{
if(w1[0] < w2[0] && w1[1] < w3[1]){
cout << w1;
if(w2[0] < w3[0])
{
cout << "\t" << w2 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w2;
}
}else if(w2[0] < w1[0] && w2[0] < w3[0]){
cout << w2;
if(w1[1] < w3[1])
{
cout << "\t" << w1 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w1;
}
}else if(w3[1] < w1[1] && w3[0] < w2[0]){
cout << w3;
if(w1[0] < w2[0])
{
cout << "\t" << w1 <<"\t" << w2;
}
else
{
cout << "\t" << w2<<"\t" << w1;
}
}
}
else if(w1[0] == w2[0] && w2[0] == w3[0])
{
if(w1[1] < w2[1] && w1[1] < w3[1]){
cout << w1;
if(w2[1] < w3[1])
{
cout << "\t" << w2 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w2;
}
}else if(w2[1] < w1[1] && w2[1] < w3[1]){
cout << w2;
if(w1[1] < w3[1])
{
cout << "\t" << w1 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w1;
}
}else if(w3[1] < w1[1] && w3[1] < w2[1]){
cout << w3;
if(w1[1] < w2[1])
{
cout << "\t" << w1 <<"\t" << w2;
}
else
{
cout << "\t" << w2<<"\t" << w1;
}
}
}
else if(w1[0] == w2[0] && w2[0] == w3[0] && w1[1] == w2[1] && w2[1] == w3[1])
{
if(w1[2] < w2[2] && w1[2] < w3[2]){
cout << w1;
if(w2[2] < w3[2])
{
cout << "\t" << w2 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w2;
}
}else if(w2[2] < w1[2] && w2[2] < w3[2]){
cout << w2;
if(w1[2] < w3[2])
{
cout << "\t" << w1 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w1;
}
}else if(w3[2] < w1[2] && w3[2] < w2[2]){
cout << w3;
if(w1[2] < w2[2])
{
cout << "\t" << w1 <<"\t" << w2;
}
else
{
cout << "\t" << w2<<"\t" << w1;
}
}
}
else
{
if(w1[0] < w2[0] && w1[0] < w3[0]){
cout << w1;
if(w2[0] < w3[0])
{
cout << "\t" << w2 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w2;
}
}else if(w2[0] < w1[0] && w2[0] < w3[0]){
cout << w2;
if(w1[0] < w3[0])
{
cout << "\t" << w1 <<"\t" << w3;
}
else
{
cout << "\t" << w3<<"\t" << w1;
}
}else if(w3[0] < w1[0] && w3[0] < w2[0]){
cout << w3;
if(w1[0] < w2[0])
{
cout << "\t" << w1 <<"\t" << w2;
}
else
{
cout << "\t" << w2<<"\t" << w1;
}
}
}
//cout << w1[0] << "\t" << "\t" <<w2[0] << "\t" << w3[0];
return 0;
}
如果有一种方法可以通过for循环但仅使用这些库
#include <iostream>
#include <stdio.h>
#include <string>
#include <algorithm>
最佳答案
我不了解您的程序尝试执行的操作。但是要考虑到std::string类具有关系运算符。因此，无需单独比较每个字符。
我将以以下方式编写程序:)您可以更改程序，要求用户输入三个字符串。
#include <iostream>
#include <string>
#include <functional>
#include <utility>
int main()
{
std::string s1 = "tom", s2 = "fox", s3 = "hello";
auto r1 = std::ref( s1 ), r2 = std::ref( s2 ), r3 = std::ref( s3 );
if ( r2.get() < r1.get() ) std::swap( r1, r2 );
if ( r3.get() < r2.get() ) std::swap( r2, r3 );
if ( r2.get() < r1.get() ) std::swap( r1, r2 );
std::cout << s1<< '\t' << s2 << '\t' << s3 << std::endl;
std::cout << r1.get() << '\t' << r2.get() << '\t' << r3.get() << std::endl;
return 0;
}
输出是
tom fox hello
fox hello tom
或者您可以使用简单的方法
#include <iostream>
#include <string>
int main()
{
std::string s1 = "tom", s2 = "fox", s3 = "hello";
if ( s1 <= s2 && s2 <= s3 )
{
std::cout << s1<< '\t' << s2 << '\t' << s3 << std::endl;
}
else if ( s1 <= s3 && s3 <= s2 )
{
std::cout << s1<< '\t' << s3 << '\t' << s2 << std::endl;
}
else if ( s2 <= s1 && s1 <= s3 )
{
std::cout << s2<< '\t' << s1 << '\t' << s3 << std::endl;
}
else if ( s2 <= s3 && s3 <= s1 )
{
std::cout << s2<< '\t' << s3 << '\t' << s1 << std::endl;
}
else if ( s3 <= s1 && s1 <= s2 )
{
std::cout << s3<< '\t' << s1 << '\t' << s2 << std::endl;
}
if ( s3 <= s2 && s2 <= s1 )
{
std::cout << s3<< '\t' << s2 << '\t' << s1 << std::endl;
}
return 0;
}
关于c++ - 如何使用C++按字母顺序对3个字符串变量进行排序？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/28798696/