String class
Example 1:Initializing
string
#include<iostream>
#include<string>
using namespace std;
int
main(){
string s;
if(s.empty()){
cout<<"string is empty "<<endl;
}
string s1(6,'B');//add 6 B's in string s1
string s2("abu bakar");//store abu bakar in string s2
string s3(s2,1,8);//stores2 from 1st
character till 8 characters in s3
string s4("you are welcome ",7);//store string till 7th character in s4
string s5;//alternative way of string
assignment
s5=" just initializing ";
cout<<endl<<"now we
start printing each string "<<endl;
cout<<" s1 = "<<s1<<endl;
cout<<" s2 = "<<s2<<endl;
cout<<" s3 = "<<s3<<endl;
cout<<" s4 = "<<s4<<endl;
cout<<" s5 = "<<s5<<endl;
}
Example 2: comparison of strings
#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;
int
main()
{
string
s1,s2,s3,s4,s5,s6,s7;
s1="Pakistan";
s2="India";
s3="Australia";
s4="Canada";
s5="Pakistan";
s6="pakistan";
s7="lovePakistan";
cout<<"s1 = "<<s1<<"\ns2 = "<<s2<<endl<<"s3 "<<s3<<endl
<<"s4
= "<<s4<<endl<<"s5
= "<<s5<<endl<<"s6
= "<<s6<<endl<<"s7
= "<<s7<<endl;
cout<<"s1.compare(s2) = "<<s1.compare(s2)<<endl;
cout<<"s1.compare(s3) = "<<s1.compare(s3)<<endl;
cout<<"s1.compare(s4) = "<<s1.compare(s4)<<endl;
cout<<"s1.compare(s5) = "<<s1.compare(s5)<<endl;//compare matched
cout<<" s1.compare(s6) = "<<s1.compare(s6)<<endl;
}
Example 3:
assignment in strings and using size() and capacity() functions
#include <iostream>
#include <string>
using namespace std;
int
main()
{
string s1,s2,s3,s4;
s2="i love programming ";
s3="C++ is the best programming language ";
s4="work hard so that you may succeed ";
cout<<" s1.size() = "<<s1.size()<<endl;
cout<<" s1.capacity() "<<s1.capacity()<<endl;
cout<<"Before making changes "<<endl<<" s1 = "<<s1<<endl<<" s2 = "<<s2
<<endl<<" s3 = "<<s3<<endl;
s1.assign(s3);
s2.assign(s3,7,18);
cout<<"after making changes "<<endl;
cout<<endl<<" s1 = "<<s1<<endl<<" s2 = "<<s2
<<endl<<" s3 = "<<s3<<endl;
cout<<"character at position 4 in s4 = "<<s4.at(3)<<endl;
cout<<"character at position 4 in s4 = "<<s4[3]<<endl;
}
Example 4:substring
of a string
#include <iostream>
#include <string>
using namespace std;
int
main()
{
string s1,s3,s4;
s1="programming is easy ";
cout<<" s1 = "<<s1<<endl;
cout<<" s1.substr(2,8) = "<<
s1.substr(2,8)<<endl<<endl;//1 way of
getting substring
string s2(s1,2,8);//2nd way of getting substring
cout<<"after doing : string s2(s1,2,8) "<<endl;
cout<<"s2 = "
<<s2<<endl<<endl;
s3=s1.substr(2,8);//assigning s3 substring of s1
cout<<"after doing : s3=s1.substr(2,8) "<<endl;
cout<<"s3 = "
<<s3<<endl<<endl<<endl;
s4="programming is difficult ";
cout<<"Before erasing s4 = "<<s4
<<endl;
cout<<"after erasing s4 = "<<s4.erase()<<endl;
if(s4.empty()){
cout<<"s4 is empty "<<endl;
}
}
Example 5:concatenation
of string , at() function,modified comparision()
#include<iostream>
#include<string>
using namespace std;
int
main(){
string
s1,s2,s3,s4,s5;
s1="cat";
s2=s1+"comb";
s3=" you are a lucky person ";
s4=" what do you do ";
cout<<" s1 = "<<s1<<endl<<" s2 = "<<s2<<endl<<" s3 = "<<s3<<endl<<" s4 = "<<s4<<endl<<endl;
s3.append(s4,4,7);
s2.swap(s1);
s5=s4.substr(2,8);
cout<<"after making following changes "<<endl;
cout<<"s3.append(s4,4,7)"<<endl<<"s2.swap(s1)"<<endl<<"s5=s4.substr(2,8)"<<endl<<endl;
cout<<" s1 = "<<s1<<endl<<" s2 = "<<s2<<endl<<" s3 = "<<s3<<endl<<" s4 = "<<s4<<endl<<" s5 = "<<s5<<endl;
string s6="i love pakistan ";
string s7="pakistan";
if((s7.compare(0,8,s6,6,8)==0));{
cout<<endl<<"comparision matched "<<endl<<endl;
}
cout<<"demonstrating at() function"<<endl<<endl;
for(int x=0;x<=s7.size()-1;x++){
cout<<x<<" = "<<s7.at(x)<<endl;
}
}
Example 6: string
erasing and finding functions
#include "stdafx.h"
#include<iostream>
#include<string>
using namespace std;
int
main(){
string s1("apple is green,mango is yellow,orange is
orange,banana is yellow");
cout<<" in string = "<<s1<<" 'is' is found at "<<s1.find("is")<<endl<<endl;
cout<<" in string = "<<s1<<" 'is' is found at from last "<<s1.rfind("is")<<endl<<endl;
cout<<"string1.find_first_of(',') is found at location =
"<<s1.find_first_of(",")<<endl;
cout<<"string1.find_last_of(',')= "<<
s1.find_last_of(',')<<endl<<endl;
cout<<"string1.find_first_not_of('aiple') = " <<s1.find_first_not_of("aiple")<<endl<<endl;
cout<<endl<<endl<<"before replacement string s1 = "<<s1<<endl<<endl;
int
position=s1.find(",");
while(position!=string::npos){
s1.replace(position,1,";;");
position=s1.find(",",position+1);
}
cout<<endl<<endl<<"after replacement string s1 = "<<s1<<endl<<endl;
}
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