scanf adds a new line character to my string automatically

Question

I'm trying to solve a basic problem where I have to print a string a output I complete my code and submitted it for test case it prints the correct output but it includes a newline character at the beginning of the output string, due to this the test case fails.

the Input is in the form of:

Arun:40:51:60
roger:49:51:62
steve:80:71:60

The output should be the name of the student with the highest score: steve

but my program outputs: " steve"

this is my program:

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
{
    int val=0,topMark=0;
    char topStudent[101];
    scanf("%d",&val);
    for(int i=0;i<val;i++)
    {
        char arr[101]; 
        int m1,m2,m3;
        scanf("%[^:]:%d:%d:%d",arr,&m1,&m2,&m3);
        if(topMark<(m1+m2+m3))
        {
            topMark=m1+m2+m3;
            strcpy(topStudent,arr);
        }
    }
    puts(topStudent[i]);   
}

I tried using both printf and puts functions, but it still prints a new line.

I'm expecting a way to get the input without the newline character at the beginning of the string or printing the string without the newline character at the beginning.

Does this answer your question? [scanf() leaves the newline character in the buffer](https://stackoverflow.com/questions/5240789/scanf-leaves-the-newline-character-in-the-buffer) — pmacfarlane, Feb 21 '23 at 17:30
Note that there are just three conversion specifiers that do not skip white space, and they are `%c`, `%n` and `%[…]` (scan sets). Include a space at the start of the format string: `" %[^:]…"`. If you printed all the student information, you'd find that `Arun` did not have a newline at the start, but both `steve` and `roger` do. — Jonathan Leffler, Feb 21 '23 at 17:32
@Vignesh Magalingam, Do not use `scanf("%[^:]...` without a _width_. In this case use `scanf(" %100[^:]` and check the return value of `scanf()`. — chux - Reinstate Monica, Feb 21 '23 at 17:45

Vlad from Moscow · Answer 1 · 2023-02-21T17:53:50.387

Add a leading space in the format string as for example

scanf(" %[^:]:%d:%d:%d",arr,&m1,&m2,&m3);
      ^^^

It allows to skip white space characters including the new line character '\n' stored in the input buffer after a preceding call of scanf.

From the C 23 Standard (7.23.6.2 The fscanf function)

5 A directive composed of white-space character(s) is executed by reading input up to the first nonwhite-space character (which remains unread), or until no more characters can be read. The directive never fails.

Here is a demonstration program.

#include <stdio.h>

int main( void )
{
    enum { N = 10 };
    char s[N];

    printf( "Enter a string (no more than %d symbols): ", N - 1 );
    scanf( "%9[^\n]", s );

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

    printf( "ENter a string (no more than %d symbols): ", N - 1 );
    scanf( " %9[^\n]", s );

    printf( "s = \"%s\"\n", s );
}

The program output might look like

Enter a string (no more than 9 symbols):      A
s = "     A"
Enter a string (no more than 9 symbols):      B
s = "B"

scanf adds a new line character to my string automatically

1 Answers1