C program to remove all extra blank spaces from string

In text processing, it is often necessary to clean up input by removing extra blank spaces from a string. This includes leading and trailing spaces as well as multiple spaces between words. This article will guide you through writing a C program to achieve this task using basic string manipulation techniques.

Steps to Solve the Problem

1. Input the String: Read the input string from the user.
2. Remove Extra Blank Spaces: Process the string to remove leading, trailing, and multiple spaces between words.
3. Print the Result: Output the cleaned string.

Write a C program to remove all extra blank spaces from string

Here is the C program to remove all extra blank spaces from a given string:

#include <stdio.h>
#include <string.h>

int main() {
    char str[200], result[200];
    int i, j = 0;

    // Input the string
    printf("Enter the string: ");
    fgets(str, sizeof(str), stdin);
    str[strcspn(str, "\n")] = '\0'; // Removing trailing newline character

    int len = strlen(str);

    // Remove leading spaces
    for (i = 0; i < len; i++) {
        if (str[i] != ' ') {
            break;
        }
    }

    // Remove extra spaces
    int space = 0;
    for (; i < len; i++) {
        if (str[i] != ' ') {
            result[j++] = str[i];
            space = 0;
        } else if (str[i] == ' ' && space == 0) {
            result[j++] = str[i];
            space = 1;
        }
    }

    // Remove trailing space if any
    if (j > 0 && result[j - 1] == ' ') {
        j--;
    }

    result[j] = '\0'; // Null terminate the result string

    printf("String after removing extra spaces: '%s'", result);

    return 0;
}

Output

Enter the string: learn    programming    at     ProCoding
String after removing extra spaces: 'learn programming at ProCoding'

Explanation of the Code

1. Input Handling: We read the input string using fgets and remove the trailing newline character using strcspn.
2. Remove Leading Spaces:
   • We iterate from the start of the string until we find the first non-space character.
3. Remove Extra Spaces:
   • We maintain a space flag to track if the current character is a space.
   • If the current character is not a space, we copy it to the result string and reset the space flag.
   • If the current character is a space and space is 0, we copy the space to the result string and set the space flag to 1. This ensures that consecutive spaces are reduced to a single space.
4. Remove Trailing Space:
   • After processing the entire string, if the last character in the result string is a space, we remove it by decrementing the index j.
5. Terminate the String:
   • We null terminate the result string.
6. Print the Result: We print the cleaned string.