menu driven mean, mode and median

#include<stdio.h>
main()
{
int i,j,count=0,m=0,c,n;
float mode,median,a[20],sum=0.0,temp,mean;
printf("enter the limite:");
scanf("%d",&n);
printf("enter your numbers:\n");
for(i=1;i<=n;i++)
{
scanf("%f",&a[i]);
sum=sum+a[i];
}

mean=sum/n;
for(i=1;i<=n-1;i++)
for(j=i+1;j<=n;j++)
if(a[i]>a[j])
{
temp=a[i];
a[i]=a[j];
a[j]=temp;
}
printf("enter your choice\n");
printf("enter 1 for mean\n");
printf("enter 2 for median\n");
printf("enter 3 for mode\n");
printf("enter 4 fo mean,median and mode\n");
scanf("%d",&c);
if(c==1||c==4)
printf("mean=%f",mean);
if(c==2||c==4)
{
if(n%2==0)
median=(a[n/2]+a[n/2+1])/2.0;
else

median=a[(n+1)/2];

printf("\nmedian=%f",median);
}
if(c==3||c==4)
{
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
if(a[i]==a[j])
count++;
}
if(m<count)
{
m=count;
mode=a[i];
}
count=0;
}
printf("\nmode=%f",mode);
for(i=1;i<=n;i++)
{
for(j=i;j<=n;j++)
{
if(a[i]==a[j])
count++;
}
if(m==count)
{
if(a[i]!=mode)
printf("\t%f ",a[i]);
}
count=0;
}
}
}