String comparison in c

Question

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

int main()
{
    char strg1[];
    char strg2[] = "football"



    printf("Enter first string: ");
    gets(strg1);

    

    if(strcmp(strg1, strg2)==0)
    {
        printf("\nEqual");
    }

    else
    {
        printf("\nNot Equal");
    }

   
    return 0;
}

I'm getting a string from the user as input and I want to compare it with a ready-made string I have, whether it's equal or not. When I try with strcmp, they are not equal. When I try with strncmp, for example, user footballABC wrote my string football is still equal because with strncmp it is 8 characters. I've limited it. Is there a solution?

Answer 1

You've done following mistakes in your program:

1. Not allocated space for char strg1[];(It will throw error while compiling).

error: definition of variable with array type needs an explicit size or an initializer char strg1[];

2. Used gets() for reading string which can lead to Buffer Overflow. while using gets() you should have been warned by compiler.

warning: this program uses gets(), which is unsafe.
Full article why gets() in not safe.

Corrected program:

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

int main()
{
    // char strg1[]; // Error!
    char strg1[100]; // Allocate space to Array.
    char strg2[] = "football";

    printf("Enter first string: ");
    scanf("%s",strg1); // Use Scanf() instead of gets().

    if(strcmp(strg1, strg2)==0)
    {
        printf("\nEqual");
    }

    else
    {
        printf("\nNot Equal");
    }

    return 0;
}