C PROGRAMMING PROGRAM • STRINGS
Compare Two Strings Without strcmp()
Learn how to compare two strings without strcmp() using a clear C program.
PROBLEM UNDERSTANDING
Input and expected output
Sample input
apple apricot
Sample output
First string comes before second
COMPLETE C PROGRAM
Complete C implementation
#include <stdio.h>
#include <string.h>
int main(void)
{
char first[200], second[200];
int index = 0;
fgets(first, sizeof first, stdin);
fgets(second, sizeof second, stdin);
first[strcspn(first, "\n")] = '\0';
second[strcspn(second, "\n")] = '\0';
while (first[index] != '\0' && first[index] == second[index]) index++;
if (first[index] == second[index]) printf("Strings are equal\n");
else if ((unsigned char) first[index] < (unsigned char) second[index]) printf("First string comes before second\n");
else printf("First string comes after second\n");
return 0;
}CURRENT STEP
SELECTED LINE
EXPECTED OUTPUT FOR THE SAMPLE
First string comes before second
Step 0 of 0
PROGRAM EXPLANATION
Algorithm and explanation
- Read the required input values.
- Advance through equal characters and compare the first differing character.
- Display the computed result.
Advance through equal characters and compare the first differing character.
EFFICIENCY
Time and space complexity
Time complexity
O(n)
Auxiliary space
O(1)
DEBUGGING CHECKLIST
Common mistakes
Check this
Use the correct format specifier for every variable.
Check this
Initialize variables before using their values.
Check this
Check braces, semicolons and input order carefully.
Try it yourself
Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.
