Trim both leading and trailing white space characters from given string

Posted on Apr 22, 2020

C program to trim both leading and trailing white space characters from given string.

Program

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#define MAX 50

void main()
{
	char str[MAX];
    int i, pos;

    printf("Enter the string\t:");
    gets(str);
    printf("\nOriginal String\t:'%s'",str);

    // learding white spaces

    pos = 0;
    while(str[pos]==' ' || str[pos]=='\t')
    {
        pos++;
    }

    if(pos != 0)
    {
        i = 0;
        while(str[i+pos]!='\0')
        {
            str[i] = str[i+pos];
            i++;
        }
        str[i] = '\0';
    }

    //trailing white spaces

    pos = -1;
    i = 0;
    while(str[i] != '\0')
    {
        if(str[i]!=' ' && str[i]!='\t')
        {
            pos = i;
        }
        i++;
    }

    str[pos + 1] = '\0';

    printf("\nModified string\t:'%s'",str);

    getch();
}

Output

Enter the string        :        welcome to coursecrux.com

Original String :'       welcome to coursecrux.com       '
Modified string :'welcome to coursecrux.com'