CODEWITHSUNDEEP
c
Gee Wiz
Gee Wiz

Reputation: 13

Display an error message?

Hi my program basically is when a user input an unrecognizable command it suppose to display an error message, however when the user input valid commands and non valid commands it still displays error message. 

int main(){

    char command[20];

    printf("Enter either add, sub, mult, div, or EXIT:\n");
    scanf("%5s", command);


    if(strcmp(command, "EXIT") || strcmp(command, "add" ) ||strcmp(command, "sub")|| strcmp(command,"div") || strcmp(command,"mult") != 0){
        printf("Warning either enter the following commands\n");

    }
    else
    {
        printf("Welcome\n");
        //function..
    }
    return 0;   
}

Also i am new to C and i am experimenting i'm not sure if that is the proper way to implement this feature.

Upvotes: 1

Views: 88

Answers (2)

tano
tano

Reputation: 896

The strcmp function returns 0 if the two strings match. Consequently your condition will always evaluate as true, since only one string can match with a certain input.

Upvotes: 0

abelenky
abelenky

Reputation: 64730

By doing:

if (strcmp || strcmp || strcmp || strcmp != 0)

You seem to be trying to check ALL the different results against 0 at the same time.

That is not how C works.
You must check each value individually

if (strcmp(command, "EXIT") &&
    strcmp(command, "add" ) &&
    strcmp(command, "sub" ) &&
    strcmp(command, "div" ) &&
    strcmp(command, "mult"))
 { /* Show Warning message */ }

Translation:
If the string is not "EXIT" and also is not "add", and also is not "sub".... then the string was not any known command; Therefore, show a warning.

Upvotes: 4

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