我正在尝试使用if语句以升序方式排列三个3号，但这不适用于第三个数字。 该怎么办？

Question

#include <stdio.h>
int main()
{
    int a, b, c, temp;
    scanf("%d %d %d", &a, &b, &c);
    if (a > b)
    {
        temp = a;
        a = b;
        b = temp;
    }
    else if (b > c)
    {
        temp = b;
        b = c;
        c = temp;
    }
    else if (c > a)
    {
        temp = c;
        c = a;
        a = temp;
    }
    printf("%d %d %d", a, b, c);
    return 0;
}

If I put 8,6,3, the output comes 6,8,3. It doesn't change the last number. I am trying to arrange three 3 numbers in ascending manner using if statement, but this doesn't work for the third number. What can be done about it?

Answer 1

It easiest if you first find the smallest, then make sure the remaining two are correct :

int main()
{
    int a, b, c, temp;

    int ret = scanf("%d %d %d", &a, &b, &c);
    if (ret != 3) {
        printf("scanf() error\n");
        exit(1);
    }

    // get smallest into a
    if ((b < a) && (b < c)) {
        temp = a;
        a = b;
        b = temp;
    } else if ((c < a) && (c < b)) {
        temp = a;
        a = c;
        c = temp;
    }

    // a is smallest, check b and c
    if (c < b) {
        temp = b;
        b = c;
        c = temp;
    }

    printf("%d %d %d", a, b, c);
    return 0;
}

Answer 2

You need to use if instead of else if as you want to compare a with b, b with c and a with c (the three and not only one of them). Moreover, as you are moving the numbers you have to take into account where they are moved for the last comparison. And your third condition was wrong. So this should be what you are trying to do:

#include <stdio.h>
int main(){
    int a, b, c, temp;
    scanf("%d %d %d", &a, &b, &c);
    if (a > b){
        temp = a;
        a = b;
        b = temp;
    }
    if (b > c){
        temp = b;
        b = c;
        c = temp;
        if (a > b){
            temp = a;
            a = b;
            b = temp;
        }
    }
    else if (a > c){
        temp = c;
        c = a;
        a = temp;
    }
    printf("%d %d %d", a, b, c);
    return 0;
}

Answer 3

I think you have misunderstood the concept of if else if structure, In your case it is not working for third number because the execution will reach to else if part only when the if condition is false.

#include <stdio.h> 
int main()
{
int a,b,c,temp;
scanf("%d %d %d",&a,&b,&c);
if(a>b)  //evaluates to true.
{
    temp=a;
    a=b;
    b=temp;
}
else if(b>c)  // not able to execute.
{
    temp=b;
    b=c;
    c=temp;
}
else if(c>a)  // not able to execute
{
    temp=c;
    c=a;
    a=temp;
}
printf("%d %d %d",a,b,c);
return 0;
}

a = 8
b = 6
c = 3

checking a>b evaluates to true hence swapped
now:

a = 6  // your output
b = 8
c = 3

you may need to go over the concept of if else structure once again

Answer 4

#include<stdio.h>

int main()
{
    int a ,b,c;
    printf("Enter the number : \n");
    scanf("%d %d %d",&a,&b,&c);
    if((a>b)&&(a>c))
    {
        if(b>c)
           printf("%d %d %d",a,b,c);
        else
           printf("%d %d %d",a ,c,b);
     }

     else if((b>c)&&(b>a))
     {
         if(c>a)
            printf("%d %d %d",b,c,a);
         else
            printf("%d %d %d",b,a,c);
     }

     else if((c>a)&&(c>b))
     {
         if(a>b)
           printf("%d %d %d",c,a,b);
         else
            printf("%d %d %d",c,b,a);
     }

    return 0; 
}

Answer 5

The easiest way is to use an array instead of three individual variables. Then use qsort for getting the input sorted.

Like:

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

// Compare function for qsort
int cmp(const void *p1, const void *p2)
{
  if (*(int*)p1 < *(int*)p2) return -1;
  if (*(int*)p2 < *(int*)p1) return 1;
  return 0;
}

int main()
{
    int arr[3];
    if (scanf("%d %d %d", &arr[0], &arr[1], &arr[2]) != 3) exit(1);

    // Sort the input
    qsort(arr, sizeof(arr)/sizeof(int), sizeof(int), cmp);

    printf("%d %d %d\n", arr[0], arr[1], arr[2]);
    return 0;
}

Answer 6

#include <stdio.h>
int main()
{
    int a,b,c,temp,min;
    scanf("%d %d %d",&a,&b,&c);
    if(a>b)
    {
        temp=a;
        a=b;
        b=temp;
    }
    if(c<a)
    {
        min=c;
        c=b;
        b=a;
        a=min;
    }
    else if(c>a && b<c) {
        min=c;
         c=b;
         b=min;
    }
    printf("%d %d %d",a,b,c);
    return 0;
}

you are comparing using else if , if any one condition satisfies it won't execute the other else condition.