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

int is_whitespace(char c)
{
    return (c == ' ' || c == '\n' || c == '\t');
}

static int find_start(const char *s)
{
    int start;
    
    start = 0;
    while (s[start] && is_whitespace(s[start]))
        start++;
    return start;
}

static int find_end(const char *s, int start)
{
    int end;

    end = strlen(s) - 1;
    while (end > start && is_whitespace(s[end]))
        end--;
    return end;
}

char *ft_strtrim(char const *s)
{
    int start;
    int end;
    int i;
    int j;
    int len;
    char *str;
    
    start = find_start(s);
    end = find_end(s, start);
    if (start > end)
        return strdup(""); // Use strdup to allocate and copy an empty string.

    len = end - start + 1;
    str = (char *)malloc(len + 1);

    if (str == NULL)
        return NULL;

    j = 0;
    i = start;
    while (i <= end)
        str[j++] = s[i++];
    str[j] = '\0';
    return str;
}

int main()
{
    const char *test_strings[] = {
        "   Hello, World!   ",
        " \t  \n  Trim Me!  \t\n ",
        "NoWhitespace",
        "",
        NULL // End marker for the test_strings array
    };

    printf("Testing ft_strtrim:\n");

    for (int i = 0; test_strings[i] != NULL; i++) {
        char *trimmed = ft_strtrim(test_strings[i]);
        if (trimmed) {
            printf("Original: \"%s\"\nTrimmed: \"%s\"\n\n", test_strings[i], trimmed);
            free(trimmed);
        } else {
            printf("Memory allocation failed for input: \"%s\"\n\n", test_strings[i]);
        }
    }

    return 0;
}

C Language online compiler

Write, Run & Share C Language code online using OneCompiler's C online compiler for free. It's one of the robust, feature-rich online compilers for C language, running the latest C version which is C18. Getting started with the OneCompiler's C editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'C' and start coding!

Read inputs from stdin

OneCompiler's C online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample C program which takes name as input and print your name with hello.

#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}