CODEWITHSUNDEEP
cstringcharacterstrtok
JeongHyun
JeongHyun

Reputation: 53

C Delete last character in string

I want to delete last character in string first, i use strtok function My Input is : "Hello World Yaho" I use " " as my delimeter

My expectation is this

Hell
Worl
Yah

But the actual output is this

Hello
Worl
Yaho

How can I solve this problem? I can't understand this output

this is my code

int main(int argc, char*argv[])
{
   char *string;
   char *ptr;
   string = (char*)malloc(100);

   puts("Input a String");
   fgets(string,100,stdin);

   printf("Before calling a function: %s]n", string);

   ptr = strtok(string," ");

   printf("%s\n", ptr);

   while(ptr=strtok(NULL, " "))
   {
      ptr[strlen(ptr)-1]=0;
      printf("%s\n", ptr);
   }

   return 0;
}

Upvotes: 5

Views: 19896

Answers (3)

chqrlie
chqrlie

Reputation: 144550

Your problem is best solved by splitting it in 2 phases: parsing the phrase into words on one hand, with strtok if you wish, and printing the words with their last character omitted in a separate function:

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

static void print_truncated_word(const char *ptr) {
    int len = strlen(ptr);
    if (len > 0) len -= 1;
    printf("%.*s", len, ptr);
}

int main(int argc, char*argv[]) {
    char buf[128];
    char *ptr;

    puts("Input a string: ");
    if (fgets(buf, sizeof buf, stdin) == NULL) {
        /* premature end of file */
        exit(1);
    }
    printf("Before calling a function: %s\n", string);

    ptr = strtok(string, " \n");
    while (ptr) {
        print_truncated_word(ptr);
        ptr = strtok(NULL, " \n");
    }
    return 0;
}

Note that the print_truncated_word function does not modify the buffer. Side effects on input arguments should be avoided, unless they are the explicit goal of the function. strtok is ill behaved to this regard, among other shortcomings such as its hidden state that prevents nested use.

Upvotes: 1

Niklas Rosencrantz
Niklas Rosencrantz

Reputation: 26652

This program deletes the last character of every word. 

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

int main(int argc, char*argv[]){

    char *string;
    char *ptr;
    string = (char*)malloc(100);
    puts("Input a String");
    fgets(string,100,stdin);
    printf("Before calling a function: %s\n", string);
    string[strlen(string)-1]=0;
    ptr = strtok(string," ");
    printf("%s\n", ptr);
    while(ptr){
        ptr[strlen(ptr)-1]=0;
        printf("%s\n", ptr);
        ptr = strtok(0, " ");
    }
    return 0;
}

You must remember to

  1. Trim the string from trailing newline
  2. Use strtok properly

Test

Input a String
Hello World Yaho
Before calling a function: Hello World Yaho

Hello
Hell
Worl
Yah

Upvotes: 4

Ronak Khandelwal
Ronak Khandelwal

Reputation: 311

Since you kept the delm as space it will create separate tokens for space separated words in your string and c-style strings contain their last characters as '\0' i.e null character so it deletes that character and not your last character in the text.

check this out http://www.cprogramming.com/tutorial/c/lesson9.html

it turns out that C-style strings are always terminated with a null character, literally a '\0' character (with the value of 0),

Upvotes: 0

Related Questions