How to Trim a String in C - Step by Step Examples

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How to Trim a String in C ?

Answer

To trim a string in C, you can create a custom function to remove leading and trailing whitespace characters.

✐ Examples

1 Trimming " Hello World "

In this example,

We create a custom function named trim that takes a string as input and removes leading and trailing whitespace characters.
We call the trim function with the string " Hello World ".
Finally, we print the trimmed string.

C Program

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

void trim(char *str) {
    int i = 0, j = strlen(str) - 1;
    while (isspace(str[i]))
        i++;
    while (j > i && isspace(str[j]))
        j--;
    str[j + 1] = '\0';
    memmove(str, str + i, j - i + 2);
}

int main() {
    char str[] = "   Hello World   ";
    trim(str);
    printf("Trimmed string is: '%s'\n", str);
    return 0;
}

Output

Trimmed string is: 'Hello World'

2 Trimming leading whitespace from " apple"

In this example,

We create a custom function named ltrim that takes a string as input and removes leading whitespace characters.
We call the ltrim function with the string " apple".
Finally, we print the trimmed string.

C Program

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

void ltrim(char *str) {
    int i = 0, j = strlen(str) - 1;
    while (isspace(str[i]))
        i++;
    memmove(str, str + i, j - i + 1);
    str[j - i + 1] = '\0';
}

int main() {
    char str[] = "   apple";
    ltrim(str);
    printf("Trimmed string is: '%s'\n", str);
    return 0;
}

Output

Trimmed string is: 'apple'

3 Trimming trailing whitespace from "banana "

In this example,

We create a custom function named rtrim that takes a string as input and removes trailing whitespace characters.
We call the rtrim function with the string "banana ".
Finally, we print the trimmed string.

C Program

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

void rtrim(char *str) {
    int i = strlen(str) - 1;
    while (isspace(str[i]))
        i--;
    str[i + 1] = '\0';
}

int main() {
    char str[] = "banana   ";
    rtrim(str);
    printf("Trimmed string is: '%s'\n", str);
    return 0;
}

Output

Trimmed string is: 'banana'

Summary

In this tutorial, we learned How to Trim a String in C language with well detailed examples.

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How to Trim a String in C - Step by Step Examples

How to Trim a String in C ?

Answer

✐ Examples

1 Trimming " Hello World "

C Program

Output

2 Trimming leading whitespace from " apple"

C Program

Output

3 Trimming trailing whitespace from "banana "

C Program

Output

Summary

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