C Programming Code Examples

C > Strings Code Examples

program to trim leading and trailing white spaces from a string

program to trim leading and trailing white spaces from a string

Write a C program to trim both leading and trailing white space characters in a string using loop. How to remove both leading and trailing white space characters in a string using loop in C programming. Logic to delete all leading and trailing white space characters from a given string in C.

Logic to remove leading and trailing white spaces

I already explained how to remove leading as well as trailing white space characters from a given string. Here in this program we will combine the logic of both in a single program.

/* C program to trim both leading and trailing white space characters from a string */

#include <stdio.h>
#define maxsize 100 // Maximum string size

/* Function declaration */
void trim(char * str);

int main()
{
    char str[maxsize];

    /* Input string from user */
    printf("Enter any string: ");
    gets(str);

    printf("\nString before trimming white space: \n'%s'", str);

    trim(str);

    printf("\n\nString after trimming white space: \n'%s'", str);

    return 0;
}

/* Remove leading and trailing white space characters */
void trim(char * str)
{
    int index, j;

    /* Trim leading white spaces     */
    index = 0;
    while(str[index] == ' ' || str[index] == '\t' || str[index] == '\n')
    {
        index++;
    }

    /* Shift all trailing characters to its left */
    j = 0;
    while(str[j + index] != '\0')
    {
        str[j] = str[j + index];
        j++;
    }
    str[j] = '\0'; // Terminate string with NULL


    /* Trim trailing white spaces     */
    j = 0;
    index = -1;
    while(str[j] != '\0')
    {
        if(str[j] != ' ' && str[j] != '\t' && str[j] != '\n')
        {
            index = j;
        }

        j++;
    }

    /* Mark the next character to last non white space character as NULL */
    str[index + 1] = '\0';
}