C Language Program Development Classic examples of two

"Program 11"

Title: Classical question: There are a pair of rabbits, from the 3rd month after the birth of a pair of rabbits each month, the rabbit long to the third month after the birth of a pair of rabbits each month, if the rabbit is not dead, ask the number of rabbits each month for how much?

1. Procedure analysis: Rabbit's rule for series 1,1,2,3,5,8,13,21 ....

2. Program Source code:

main()
{
long f1,f2;
int i;
f1=f2=1;
for(i=1;i<=20;i++)
　{ printf("%12ld %12ld",f1,f2);
　　　if(i%2==0) printf("\n");/*控制输出，每行四个*/
　　　f1=f1+f2; /*前两个月加起来赋值给第三个月*/
　　　f2=f1+f2; /*前两个月加起来赋值给第三个月*/
　}
}

"Program 12"

Title: Determine how many primes there are between 101-200, and output all primes.

1. Procedure analysis: To determine the method of prime number: To remove 2 to sqrt (this number), if divisible, it indicates that this number is not prime, conversely is prime.

2. Program Source code:

#include "math.h"
main()
{
　int m,i,k,h=0,leap=1;
　printf("\n");
　for(m=101;m<=200;m++)
　　{ k=sqrt(m+1);
　　　for(i=2;i<=k;i++)
　　　　　if(m%i==0)
　　　　　　{leap=0;break;}
　　　if(leap) {printf("%-4d",m);h++;
　　　　　　　　if(h%10==0)
　　　　　　　　printf("\n");
　　　　　　　 }
　　　leap=1;
　　}
　printf("\nThe total is %d",h);
}