How to check string in if condition?

Question

1.00/5 (1 vote)

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Why this if condition is not working when i need to check string from user?

C++

#include <stdio.h>
main()
{
    char a;
    printf("Enter the Name\n");
    scanf("%d",&a);

    if(a=='xyz')
    {
        printf("You enter xyz");
    }

    if(a=='abc')
    {
        printf("You enter abc");
    }   
}

I also try this one but even not working

#include <stdio.h>
main()
{
    char a;
    printf("Enter the Name\n");
    scanf("%c",&a);

    if(a=='xyz')
    {
        printf("You enter xyz");
    }

    if(a=='abc')
    {
        printf("You enter abc");
    }
}

Posted 27-Mar-13 3:17am

vishal2592

Updated 27-Mar-13 3:27am

Jonathan [Darka]

v2

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4 solutions

Solution 4

Quote:
char a;
printf("Enter the Name\n");
scanf("%c",&a);

change to

C

char a[256];
printf("Enter the name\n");
fgets(a, 256, stdin);

Quote:
if(a=='xyz')
{
printf("You enter xyz");
}
if(a=='abc')
{
printf("You enter abc");
}

change to:

C

if (strcmp(a, "xyz") == 0)
{
  printf("You entered xyz\n");
}
else if (strcmp(a, "abc")==0)
{
  printf("You entered abc\n");
}

You may also simply write:

C

printf("You entered %s\n", a);

Note you must include string.h in order to use strcmp.

[UPDATE]
You are right, I forgot the "annoying newline NOT discarded by fgets". Try:

C

#include <stdio.h>
#include <string.h>
int main() {
  char a[256]={0};
  int len;
  printf("Enter the Name\n");

  if ( fgets(a,256,stdin) )

  // replace the possibly 'not-discarded' newline with string terminator
  len = strlen(a);
  if (len>0 && a[len-1]=='\n')
    a[len-1]='\0';

  if (strcmp(a, "xyz") == 0)
  {
    printf("You entered xyz\n");
  }
  else if (strcmp(a, "abc")==0)
  {
  printf("You entered abc\n");
  }
  printf("'%s'\n", a);
  return 0;
}

[/UPDATE]

Posted 27-Mar-13 3:31am

CPallini

Updated 27-Mar-13 4:21am

v2

Comments

vishal2592 27-Mar-13 9:44am

I try this one
main()
{
char a[256];
printf("Enter the Name\n");
fgets(a,256,stdin);
if (strcmp(a, "xyz") == 0)
{
printf("You entered xyz\n");
}
else if (strcmp(a, "abc")==0)
{
printf("You entered abc\n");
}
}
I used string.h
But event not working?

Solution 1

Try:

scanf("%s", &a)

Plus, you'll need to change the definition of a to a character array of a suitable size.

Posted 27-Mar-13 3:26am

Jonathan [Darka]

Updated 27-Mar-13 3:28am

v2

Solution 2

Your Code is wrong.
In your Code you are compairing a character (a) with a string (abc or xyz) instead of scanf for taking the input use gets(a) to take the input then only your input will be considered as string.

Let me Know in case you need some other information.

Posted 27-Mar-13 3:27am

AyushJain1890

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OriginalGriff · Accepted Answer · 2013-03-27T03:29:00

Solution 3

Jonathon has the right idea, but even once you have read the string from teh user correectly, you can't just use "==" to compare two strings - all it will do is compare a variable string address with a fixed string address and will always fail to match.

You need to look at using strcmp[^] instead to compare the string content:

C++

if (strcmp(a, "xyz") == 0)
   {
   ...
   }

Posted 27-Mar-13 3:29am

OriginalGriff

Comments

Thomas Daniels 27-Mar-13 9:38am

+5!

Jonathan [Darka] 27-Mar-13 17:18pm

Damn, I was too focused on the scanf to notice that :)