Programming in C of FC tutorial
Apr 7, 2014Technology
###Programming In C
GCC’s funcitionality:
gcc command calls a compiler(which transforms a higher level language into assembler), an assembler translates assembler into object files(machine instructions), and a linker, which combines several object files into an executable.
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###Programming In C II Example code:
#include <stdio.h>
#define VERSION "1.0"
/*
* Runs a prime check on a given integer, return
* 1 when the integer is a prime number, 0 otherwise
*/
int isPrime(int prime)
{
int count = 2;
// Catch two special cases
if(prime == 1)
{
return 0;
}
else if(prime == 2)
{
return 1;
}
else
{
while(prime % count != 0 && count*count<=prime)
{
count++;
}
return (prime%count==0)?0:1;
}
}
/*
* Print version information
*/
void printVersion()
{
printf("Primality checker version %s\n", VERSION);
printf("Compiled on %s %s\n", __DATE__, __TIME__);
}
int main()
{
int i = 1;
const int max_prime = 2500;
printVersion();
for (i = 1; i<max_prime; i++)
{
if(isPrime(i))
{
printf("%d is prime\n", i);
}
else
{
printf("%d is not prime\n", i);
}
}
return 0;
}
####Execise 1 Rewrite the for loop in the main() function so it becomes a while loop.
//for (i = 1; i<max_prime; i++)
while(i<max_prime)
{
if(isPrime(i))
{
printf("%d is prime\n", i);
}
else
{
printf("%d is not prime\n", i);
}
i++;
}
####Execise 2 Rewrite the if…else if…else structure in the isPrime() function to a switch…case structure.
int count = 2;
int returnvalue = 0;
// Catch two special cases
switch(prime)
{
case 1:
returnvalue = 0;
break;
case 2:
returnvalue = 1;
break;
default:
while(prime % count != 0 && count*count <= prime)
{
count++;
}
returnvalue = (prime % count == 0)?0:1;
}
return returnvalue;
####Execise 3 Rewrite the ternary(condition)?value1:value2 to an if..else structure
//return (prime%count==0)?0:1;
if(prime%count == 0)
{
return 0;
}
else
{
return 1;
}
####Execise 4 Rewrite the if…else in the main() funciton to make sure the ternary operator
/*
if(isPrime(i))
{
printf("%d is prime\n", i);
}
else
{
printf("%d is not prime\n", i);
}
*/
printf("%d %s prime\n", i, isPrime(i)?"is":"is not");
####Execise 5 Replace the isPrime() function by an isOdd() function which return 1 when a given integer is odd.
int isOdd(int odd)
{
if(odd == 1)
{
return 1;
}
else
{
if(odd%2 == 0)
{
return 0;
}
else
{
return 1;
}
}
}
/* Called via */
if(isOdd(i))
{
printf("%d is Odd\n", i);
}
else
{
printf("%d is not Odd\n", i);
}
####Execise 6 Design and write a small application which print out the n Fibonacci sequence, where n should be easily modifiable.
#include <stdio.h>
/* The formula is like
* a(n+2) = a(n)+a(n+1)
* while when a1 = 1, a2 =1
*/
int Fib(int fib)
{
if(fib == 1)
{
return 1;
}
else if(fib == 2)
{
return 1;
}
else
{
return (Fib(fib-1) + Fib(fib-2));
}
}
int main(int argc, char **argv)
{
int i;
int j = 1;
printf("Please input an integer number\n");
scanf("%d", &i);
printf("The Fibonacci sequence is: \n");
for( j = 1; j <= i; j++)
{
printf("a[%d] is %d.\n", j, Fib(j));
}
return 0;
}
Because we use recursion here, when the n is too big, the calculation maybe very slow.