C Programming: Compare two strings without using string library functions
C String: Exercise-6 with Solution
Write a program in C to compare two strings without using string library functions.
Sample Solution:
C Code:
// C program to compare the two strings without using strcmp() function
#include <stdio.h>
#define str_size 100 // Declare the maximum size of the string
// Function to compare two strings
int test(char* s1, char* s2) {
int flag = 0; // Initialize a flag variable to indicate string equality or inequality
// Loop to compare characters in the strings until null terminator '\0' is found in both strings
while (*s1 != '\0' || *s2 != '\0') {
if (*s1 == *s2) { // Check if the characters in both strings are equal
s1++; // Move to the next character in the first string
s2++; // Move to the next character in the second string
} else if ((*s1 == '\0' && *s2 != '\0') || (*s1 != '\0' && *s2 == '\0') || *s1 != *s2) {
// Check for cases where one string ends before the other or characters at the same index are not equal
flag = 1; // Set the flag to indicate inequality
break; // Exit the loop as inequality is found
}
}
return flag; // Return the flag indicating string equality (0) or inequality (1)
}
// Main function
int main(void) {
char str1[str_size], str2[str_size]; // Declare character arrays for the two strings
int flg = 0; // Initialize a flag variable
printf("\nInput the 1st string : ");
fgets(str1, sizeof str1, stdin); // Read the first string from the standard input (keyboard)
printf("Input the 2nd string : ");
fgets(str2, sizeof str2, stdin); // Read the second string from the standard input (keyboard)
printf("\nString1: %s", str1); // Display the first string
printf("String2: %s", str2); // Display the second string
flg = test(str1, str2); // Call the function to compare the strings
// Display the comparison result based on the flag value
if (flg == 0) {
printf("\nStrings are equal.\n");
} else if (flg == 1) {
printf("\nStrings are not equal.");
}
return 0; // Return 0 to indicate successful program execution
}
Sample Output:
Check the length of two strings: -------------------------------- Input the 1st string : aabbcc Input the 2nd string : abcdef String1: aabbcc String2: abcdef Strings are not equal.
Sample Output:
Check the length of two strings: -------------------------------- Input the 1st string : aabbcc Input the 2nd string : aabbcc String1: aabbcc String2: aabbcc Strings are equal.
Flowchart:
C Programming Code Editor:
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