C Program to Extract a Portion of String

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C Program to Extract a Portion of String

Vinay Khatri
Last updated on June 16, 2024

    Extracting a substring from a string is one of the most common operations that you may need to use in your code. In C, it is quite easy to extract a portion of a string with the intention of using it separately from the parent string.

    In this tutorial, we have written a C program that can extract a substring from a given string. However, before sharing the C program, let's take a look at the steps that the program follows to extract a substring from the string input by a user.

    Steps to Create the Program

    • Ask the user to enter a string.
    • Ask the user to enter the starting and endpoint of the string they want to extract. These points will represent the index value of the String.
    • Pass the string, starting point, and ending point as the arguments to the user-defined function sub_string().
    • The sub_string() function prints a sequence of characters that represents the substring that the user has requested.

    C Program to Extract a Portion of a String

    #include <conio.h>
    void sub_string(char *s, int start,int end)
           int i;
           for(i=start; i<= end; i++)
    void main()
          char str[100];
          int s,e;
          printf("Enter a String: ");
          printf("Enter the starting Index: ");
          printf("Enter the Last Index: ");
          if(e > strlen(str) || (s>strlen(str)))
                printf("Starting or End value of Index is out of Range");


    Enter a String: Welcome To TechGeekBuzz
    Enter the starting Index: 1
    Enter the Last Index: 9
    elcome To

    Note: gets(): It is an in-built C function that can take string input from the user, and it is similar to the scanf() function.

    To Sum it Up

    Extracting a substring from a string in C is quite simple. In our program above, we have written a function that accepts three arguments, namely the input string, the starting index number, and the ending index number, and outputs a substring.

    Also, the C program that extracts a portion of a string prompts a user to input the string along with the starting and ending index number to extract the substring.

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