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[Solved] I made program to reverse a string, it runs but ads NULL at the end.

By: IncludeHelp, On 02 NOV 2016

This is a solution of a program; we published it after fix the issues; in this program we will learn how we can read a string character by character and print the string in reverse order (character by character)?

This program is asked from our regular reader Mr. SHAKTI TRIPATHI.

His question was:
I made program to reverse a string, it runs but adds '0' (string termination character) at the end. I don't want '0' to be displayed on output window.
Could It be removed in anyway?. I am sending you code below..

        
#include<stdio.h>
#include<conio.h>

int main(){

int ch,count=0,i;
char str[100] ;
ch=getchar();

while(ch!='\n'){
    str[count]=ch;
    count++;
    ch=getchar();
}
i=count-1;
while(i>=0){
    putchar(str[i] );  //print in reverse.
    i=i-1;
}
printf("%s ",str[i] );

return 0;
}        
        
        

Here is the solution of the above problem; let’s consider the following program

#include<stdio.h>

int main()
{
	int ch,count=0,i;
	char str[100] ;

	printf("Enter string: ");
	ch=getchar();

	while(ch!='\n'){
		str[count]=ch;
		count++;
		ch=getchar();
	}
	
	printf("Entered string is: ");
	i=count-1;
	while(i>=0){
		putchar(str[i] );  //print in reverse.
		i=i-1;
	}
	printf("\n");
	return 0;
}

Output

    Enter string: Hello World.
    Entered string in reverse order is: .dlroW olleH

What was the problem?

• There is no need to print last character after the while loop body; so we removed printf("%s ",str[i] ); after the while loop.
• Added two print statement to understand program better.
  • printf("Enter string: "); before reading characters.
  • printf("Entered string is: "); before printing the string in reverse order.
• No need to include <conio.h> if there is no getch() or clrscr() function, so we removed this header file inclusion.