C++ program to check if the given string is palindrome or not
Check whether a String is a Palindrome
Today in this article we will learn how to check whether a String is a Palindrome using C++ Programming language. Different methods to write String Palindrome Program in C++
A string is palindrome if the reverse and the original string is same
Lets understand this with the help of an example:-
- Input sting:- AMA
- Reverse sting:- AMA
Here AMA = AMA so this is a palindrome
Algorithm:
- Initialize the variable.
- Accept the input.
- Initialize for loop.
- Check if string is palindrome or not.
- Terminate for loop.
- Print result.
Method 1: C++ programming code to check if a given string is palindrome or not
Run
// String palindrome program in c++
#include <iostream>
#include <stdio.h>
using namespace std;
void Lower_case(char str[]){
int i = 0;
while (str[i] != '\0')
{
if (str[i] > 64 && str[i] < 91)
str[i] += 32;
i++;
}
}
// A function to check if a string str is palindrome
void CheckPalindrome(char str[]) {
// Start from leftmost and rightmost corners of str
int l = 0;
int h = strlen(str) - 1;
// Keep comparing characters while they are same
Lower_case(str);
while (h > l) {
if (str[l++] != str[h--]) {
cout << "The String " << str << " is not a palindrome\n";
return;
}
}
cout << "The String " << str << " is a palindrome";
}
// Driver program to test CheckPalindrome function int main() {
char str1[50] = "naman"; // size of char string
CheckPalindrome(str1);
cout<<endl;
char str2[50] = "radar"; // size of char string
CheckPalindrome(str2);
return 0;
}
Output
The String naman is a palindrome The String radar is a palindrome
Note
In this C++ program to check a string is a palindrome or not we will iterate first half of the string through a for loop and will compare it with remaining half as we need to find if first and last, second and second last, and so in the string are equal or not. If these characters are equal then the string is palindrome else it is not.
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Method 2
We can also Check whether a String is Palindrome with another method given below:-
- The approach is to transfer the string to another string in a reverse manner let the another array is rev.
- All we need is the size of the string.
- The method is to initialize a character array of the equal size and start copying the elements of the input string from the end.
- And then check the rev and the original string and if both are same then its is palindrome else its not palindrome
Run
#include <iostream>
#include <stdio.h>
using namespace std;
void Lower_case(char str[]) {
int i = 0;
while (str[i] != '\0') {
if (str[i] > 64 && str[i] < 91) str[i] += 32;
i++;
}
}
int main() {
char str[10] = "nAman", rev[1000];
int i, j, count = 0;
cout << "String Before Reverse: " << str << endl;
// finding the length of the string
while (str[count] != '\0') {
count++;
}
j = count - 1;
Lower_case(str);
// reversing the string by storing it in another array
for (i = 0; i <= count; i++) {
rev[i] = str[j];
j--;
}
cout << "String After Reverse:" << rev << endl;
int res = strcmp(str, rev);
if (res == 0) {
cout << str << " is Palindrome";
} else {
cout << str << " Not palindorme";
}
return 0;
}
Output
String Before Reverse: nAman
String After Reverse:naman
naman is Palindrome
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#include
using namespace std;
int main(){
string str1,str2;
cin>>str1;
str2=str1;
reverse(str1.begin(),str1.end());
if(str2==str1){
cout<<"yes";
}
else cout<<"No";
return 0;
}
That’s Very Simple. Great 😉
Good to hear that <3
Text us here if needed any help from us<3
if we apply this logic, then we won’t get proper output. use this code to get proper output.#include
using namespace std;
int main(){
char str[100];
cin>>str;
int c=0;
int len=strlen(str);
int count=0;
for(int i=0;i<len/2;i++){
if(str[i]!=str[len-i-1])
c=1;
break;
}
if(c==0)
std::cout << "palindrome" << std::endl;
else
cout<<"no"<<endl;
}