﻿ C Program: Check if a given number is circular prime or not - w3resource

# C Exercises: Check if a given number is circular prime or not

## C Numbers: Exercise-27 with Solution

Write a program in C to check if a given number is circular prime or not.

Test Data
Input a Number: 1193

Sample Solution:

C Code:

``````# include <stdio.h>
# include <stdlib.h>
# include <stdbool.h>
# include <math.h>

int flg;
void chkPrime(long int n)
{
long int i;
i=n-1;
while(i>=2)
{
if(n%i==0)
{
flg=1;
}
i--;
}
}
void AllCombination(long int a)
{
long int b1,c1,d1,e1,i,j,k,s1,z1,v1,x[8],y[8],m;
b1=a;
i=0;
while(b1>0)
{
y[i]=b1 % 10;
b1=b1/10;
i++;
}
c1=0;
for(j=i-1;j>=0;j--)
{
x[c1]=y[j];
c1++;
}
m=i;
while(m>0)
{
c1=m-1;
d1=i-1;
e1=0;
s1=0;
while(e1<i)
{
z1=pow(10,d1);
v1=z1*x[c1%i];
c1++;
d1--;
e1++;
s1=s1+v1;
}
m--;
chkPrime(s1);
}
}
int main()
{
long int num1;
printf("\n\n Check whether a given number is circular prime or not: \n");
printf(" -----------------------------------------------------------\n");
printf(" Input a Number: ");
scanf("%li",&num1);
flg=0;
AllCombination(num1);
if(flg==0)
{
printf(" The given number is a circular prime Number.\n");
}
else
{
printf(" The given number is not a circular prime Number.\n");
}
return 0;
printf("\n");
}
```
```

Sample Output:

``` Input a Number: 1193
The given number is a circular prime Number.
```

Pictorial Presentation:

Flowchart:

C Programming Code Editor:

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## C Programming: Tips of the Day

It is more efficient to use if-return-return or if-else-return?

Since the return statement terminates the execution of the current function, the two forms are equivalent (although the second one is arguably more readable than the first).

The efficiency of both forms is comparable, the underlying machine code has to perform a jump if the if condition is false anyway.

Note that Python supports a syntax that allows you to use only one return statement in your case:

return A+1 if A > B else A-1

Ref : https://bit.ly/2S4P2he

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