Best way to compare two int arrays of the same len

问题:

what is the best way to compare int arrays b and c with a:

int a[] = {0,1,0,0,1};
int b[] = {0,1,0,0,1};
int c[] = {1,1,0,0,1};

b and c are just examples, assume they can be any combination of 0s and 1s.

I am trying to detect arrays identical to a. I have googled this for a while and have not found a satisfactory answer.

This is a beginners question I realise, thank you for your patience.

回答1:

Use the standard memcmp function from <string.h>.

memcmp(a, b, sizeof(a)) == 0

whenever a and b are equal.

回答2:

If you mean

int a[] = {0,1,0,0,1};
int b[] = {0,1,0,0,1};
int c[] = {1,1,0,0,1};

then

memcmp(a, b, sizeof(a)); /* returns zero for a match */
memcmp(a, c, sizeof(a)); /* returns nonzero for no match */

回答3:

Use a loop and compare the individual elements one after another.

回答4:

More information is needed on the question. I can divide your question in two ways as below,

1. Compare array contents considering order?? Ex:char a[]={a, b, c}, b[]={a, c, b} here since you are considering the order, the contents are not same so a!=b

---

2. compare array contents irrespective of order? Ex:char a[]={a, b, c}, b[]={a, c, b} here if you are not considering the order, the contents are same so a==b

---

Solution for Question no 1: One can use memcmp for this problem. Because memcmp will compare lexicographical and return 0 or 1 or -1 as below

 #include<stdio.h>
    #include<string.h>
    int main()
    {

        char a[]={'a','b','c'};
        char b[]={'a','b','c'};
        int x=memcmp(a,b,sizeof(a));
        printf("%d\n",x);

    return 0;
    }
***output:0***

    #include<stdio.h>
    #include<string.h>
    int main()
    {

        char a[]={'a','c','b'};
        char b[]={'a','b','c'};
        int x=memcmp(a,b,sizeof(a));
        printf("%d\n",x);

    return 0;
    }
***output:1***

    #include<stdio.h>
    #include<string.h>
    int main()
    {

        char a[]={'a','b','c'};
        char b[]={'b','a','c'};
        int x=memcmp(a,b,sizeof(a));
        printf("%d\n",x);

    return 0;
    }
***output:-1***

Solution for Question no 2: One can use memcmp for this problem, the best solution for this problem is as below

Here, I answered for the above problem https://stackoverflow.com/a/36130812/5206646