Question

Write a C program, named sortit, that reads three integers from the command line argument and returns the sorted list of the integers on the standard output screen, For instance,

>sortit 3 5 7

>The sorted list is 3, 5, 7.

>sortit 4 0 9

>The sorted list is 0, 4, 9

>sortit 1 p 9

>sortit: invalid input p.

>sortit

>usage: sortit num1 num2 num3!

1. The source code of a c file

2. Screenshots that show successful execution of your testing cases including 1. invalid input, 2. wrong usage (not enough arguments), 3. correct input and output as expected.

Answer 1

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

#define min(a,b) ((a)<(b)?(a):(b))
#define max(a,b) ((a)>(b)?(a):(b))

int isNumber(char *s) {
    int i = 0;
    while(s[i] != '') {
        if (!isdigit(s[i])) {
            return 0;
        }
        i++;
    }
    return 1;   
}

int main(int argc, char *argv[]){

    if(argc != 4) {
        printf("usage: sortit num1 num2 num3!");
        exit(0);
    }

    if(!isNumber(argv[1])) {
        printf("sortit: invalid input %s
", argv[1]);
        return 1;
    }   
    if(!isNumber(argv[2])) {
        printf("sortit: invalid input %s
", argv[2]);
        return 1;
    }   
    if(!isNumber(argv[3])) {
        printf("sortit: invalid input %s
", argv[3]);
        return 1;
    }

    int a = atoi(argv[1]);
    int b = atoi(argv[2]);
    int c = atoi(argv[3]);


    int lo = min(min(a, b), c);
    int hi = max(max(a, b), c);
    int mid = (a + b + c) - (lo + hi);

    printf("The sorted list is %d, %d, %d.
", lo, mid, hi);

    return 0;
}

Please upvote, as i have given the exact answer as asked in question. Still in case of any concerns in code, let me know in comments. Thanks!