How come my program won't recognize another command?

Question

I am currently writing a program's main function(the bare-bone function so far) so far I've only included the "end" command to end the program. Whenever anything else is typed that isn't a command, it will output an error message. However, now that I'm inputting more commands within the loop, it doesn't seem to be recognizing anything else. I'm writing a program that creates polynomials after prompting the user to enter coefficients and exponents.

The command is adc(add coefficient command) and after a space you're supposed to add an integer standing for the coefficient and another space with another integer standing for the exponent.

Example: adc 4 5 Output: 4x^5

int main(void){
    char buf[5]; //Creates string array
    unsigned int choice;
    printf("Command? "); // Prompts user for command
    fflush(stdout);
    gets(buf); //Scans the input

    while(strncmp(buf, "end", 3) != 0) //Loop that goes through each case, so long as the command isn't "end".
    {
        switch( choice ){
        //Where the other cases will inevitably go
            if((strcmp(buf,"adc %d %d"))== 0){
            }
        break;
            default:
              printf("I'm sorry, but that's not a command.\n"); //Prints error message if input is not recognized command
    fflush(stdout);
              break;
        }
        printf("Command? "); //Recycles user prompt
        fflush(stdout);
        gets(buf);
    }
    puts("End of Program."); //Message displayed when program ends
}

Answer 1

You can't use a format string like this: strcmp(buf,"adc %d %d") to test for a certain kind of input. Your strcmp will only signal string equality if the use inputs literally: "adc %d %d" , not adc followed by two integers.

You'll need to parse the input string manually, by tokenizing around whitespace characters, checking the first token with strcmp against eg adc , then parsing the numbers separately.

I don't notice any case statements in your switch . It looks like you can just remove the switch , since you're not using choice anywhere.

Also, don't use gets , use fgets instead.