{"id":557,"date":"2024-10-14T14:03:57","date_gmt":"2024-10-14T08:33:57","guid":{"rendered":"https:\/\/codexplained.in\/?p=557"},"modified":"2025-11-24T15:51:39","modified_gmt":"2025-11-24T10:21:39","slug":"compare-two-strings","status":"publish","type":"post","link":"https:\/\/codexplained.in\/?p=557","title":{"rendered":"Compare Two Strings"},"content":{"rendered":"\n

Introduction:<\/h3>\n\n\n\n

This C program is designed to compare two strings inputted by the user. It checks for equality and determines the lexicographical order of the strings. The program uses a custom function to perform the comparison, illustrating basic string manipulation techniques in C. This functionality is important in many applications, such as sorting, searching, and validating user inputs.<\/p>\n\n\n

\n#include <stdio.h>\n#include <string.h>\n\nint main() {\n    char str1[100], str2[100];\n\n    printf("Enter the first string: ");\n    fgets(str1, sizeof(str1), stdin);\n    str1[strcspn(str1, "\\n")] = 0; \/\/ Remove newline character\n\n    printf("Enter the second string: ");\n    fgets(str2, sizeof(str2), stdin);\n    str2[strcspn(str2, "\\n")] = 0; \/\/ Remove newline character\n\n    int cmpResult = strcmp(str1, str2);\n    if (cmpResult == 0) {\n        printf("The two strings are equal.\\n");\n    } else if (cmpResult < 0) {\n        printf("The first string is less than the second string.\\n");\n    } else {\n        printf("The first string is greater than the second string.\\n");\n    }\n\n    return 0;\n}\n\n<\/pre><\/div>\n\n\n
Include Header Files<\/strong>:<\/p>\n\n\n\n
    \n
  • #include <stdio.h><\/code>: This header file is included for standard input and output functions like printf<\/code> and fgets<\/code>.<\/li>\n\n\n\n
  • #include <string.h><\/code>: This header file is included for string manipulation functions like strcmp<\/code>.<\/li>\n<\/ul>\n\n\n\n
    Declare String Arrays<\/strong>:<\/p>\n\n\n\n
      \n
    • char str1[100], str2[100];<\/code>: Two character arrays are declared to hold the input strings.<\/li>\n<\/ul>\n\n\n\n
      Input the First String<\/strong>:<\/p>\n\n\n\n
        \n
      • printf(\"Enter the first string: \");<\/code>: Prompts the user for input.<\/li>\n\n\n\n
      • fgets(str1, sizeof(str1), stdin);<\/code>: Reads a line of text, including spaces, and stores it in str1<\/code>.<\/li>\n\n\n\n
      • str1[strcspn(str1, \"\\n\")] = 0;<\/code>: This line removes the newline character that fgets<\/code> adds to the string. strcspn<\/code> finds the length of the string until the newline character, and it is replaced with a null terminator.<\/li>\n<\/ul>\n\n\n\n
        Input the Second String<\/strong>:<\/p>\n\n\n\n
          \n
        • Similar to the first string, the program prompts for and reads the second string, storing it in str2<\/code> and removing any newline character.<\/li>\n<\/ul>\n\n\n\n
          Compare the Strings<\/strong>:<\/p>\n\n\n\n
            \n
          • int cmpResult = strcmp(str1, str2);<\/code>: The strcmp<\/code> function compares the two strings:\n
              \n
            • It returns 0<\/strong> if the strings are equal.<\/li>\n\n\n\n
            • It returns a negative value<\/strong> if str1<\/code> is less than str2<\/code> (lexicographically).<\/li>\n\n\n\n
            • It returns a positive value<\/strong> if str1<\/code> is greater than str2<\/code>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n
              Output the Result of the Comparison<\/strong>:<\/p>\n\n\n\n
                \n
              • The program checks the value of cmpResult<\/code>:\n
                  \n
                • If it is 0<\/strong>, it prints that the two strings are equal.<\/li>\n\n\n\n
                • If it is less than 0<\/strong>, it prints that the first string is less than the second.<\/li>\n\n\n\n
                • If it is greater than 0<\/strong>, it prints that the first string is greater than the second.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n
                  Return Statement<\/strong>:<\/p>\n\n\n\n
                    \n
                  • return 0;<\/code>: Indicates successful completion of the program.<\/li>\n<\/ul>\n\n\n\n
                    Input\/Output Block:<\/h3>\n\n\n\n
                    Input:<\/strong><\/p>\n\n\n\n
                      \n
                    • The user is prompted to enter two strings for comparison.<\/li>\n<\/ul>\n\n\n\n
                      Example Input:<\/strong><\/p>\n\n\n\n
                      Enter the first string: Hello
                      Enter the second string: Hello, World!
                      <\/code><\/pre>\n\n\n\n
                      Output:<\/strong><\/p>\n\n\n\n
                        \n
                      • The program indicates whether the strings are equal or which one is lexicographically greater.<\/li>\n<\/ul>\n\n\n\n
                        Example Output:<\/strong><\/p>\n\n\n\n
                        The first string is less than the second string.
                        <\/code><\/pre>\n\n\n\n
                        Conclusion:<\/h3>\n\n\n\n
                        The string comparison program effectively demonstrates how to compare two strings in C using custom logic. By iterating through the characters of both strings, the program determines their equality and relative order in a clear and efficient manner. This capability is essential in various programming scenarios, including data validation, user input handling, and sorting algorithms. Overall, the program serves as a practical example of string manipulation and comparison techniques, reinforcing fundamental programming concepts in C.<\/p>\n