Find mean,median and mode using c program

#include<stdio.h>
main()
{
int i,j,a[20]={0},sum=0,n,t,b[20]={0},k=0,c=1,max=0,mode;
float x=0.0,y=0.0;
printf("\nEnter the limit\n");
scanf("%d",&n);
printf("Enter the set of numbers\n");
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
sum=sum+a[i];
}
x=(float)sum/(float)n;
printf("Mean\t= %f",x);

for(i=0;i<n;i++)
{
for(j=i+1;j<n;j++)
{
if(a[i]>a[j])
{
t=a[i];
a[i]=a[j];
a[j]=t;
}
}
}
if(n%2==0)
y=(float)(a[n/2]+a[(n-1)/2])/2;
else
y=a[(n-1)/2];
printf("\nMedian\t= %f",y);

for(i=0;i<n-1;i++)
{
mode=0;
for(j=i+1;j<n;j++)
{
if(a[i]==a[j])
{
mode++;
}
}
if((mode>max)&&(mode!=0))
{
k=0;
max=mode;
b[k]=a[i];
k++;
}
else if(mode==max)
{
b[k]=a[i];
k++;
}
}
for(i=0;i<n;i++)
{
if(a[i]==b[i])
c++;
}
if(c==n)
printf("\nThere is no mode");
else
{
printf("\nMode\t= ");
for(i=0;i<k;i++)
printf("%d ",b[i]);
}
}