String Comparison in C and C++ Languages and Working of strcmp function

In both C and C++ programming languages, an inbuilt function strcmp() is used to compare two strings. This function is defined in string.h header file. So, to use this function, you have to include the header file string.h in the program. Most of the people ( i mean beginners) have a wrong idea about the working of the this function. I also had made some false assumptions. This function takes two strings as arguments. And it compares the two strings using the ASCII equivalent of each character. Some of the false ideas about this function are:

• The function returns 1 when the strings are equal and 0 when they are not equal
• The function returns 1 when they are not equal
• The function returns 1 when the first string is greater than the second and returns -1 when the first one is less than the second one

C and C++ Programs for String Sorting

Here i am writing programs in c and c++ languages to sort a given number of strings. Sorting is carried out based on the ASCII values of the letters in the strings. The string comparing function strcmp() is used in the program. These programs sort a given set of strings in ascending order.To change it into descending order just replace > with < in comparison line. The comparison line in the code is marked by comment.

C Program:

#include<stdio.h>
#include<string.h>
#include<conio.h>
void main()
{

C Program to Check Whether a Given String is Palindrome or Not

Here i am writing two different programs two check whether an input string is palindrome or not. The first program checks the string manually character by chatter from both ends. The other program make use of a string function strrev() (under string.h) to reverse the string. Therefore, the second program is more compact.

Program 1:

#include<stdio.h>

#include<string.h>

void main()

{

char a[20];

int i, len;

printf("\nEnter the string:\n");

gets(a);

len = strlen(a);

for (i = 0; i < len / 2; i++)

{

if (a[i] != a[len - i - 1])

break;

}