1.Fibonacci数列,兔子繁殖问题
#include <stdio.h> int main() { int f1=1, f2=1; int i; for (i = 1; i <= 20; i++) { printf("%12d %12d ", f1, f2); if (i % 2 == 0) printf("\n"); f1 = f1 + f2; f2 = f2 + f1; } return 0; }
2.输入一个大于3的整数n,判定是否为素数
#include <stdio.h> #include<math.h> int main() { int n, i, k; printf("please enter a integer number,n=?"); scanf_s("%d", &n); k = sqrt(n); for (i = 2; i <=k; i++) if (n%i == 0)break; if (i < k) printf("%d is not a prime number.\n", n); else printf("%d is a prime number.\n", n); return 0; }
#include<stdio.h> #include<math.h> int main() { int i, k, n, m = 0; for (n = 101; n <= 200; n = n + 2) { k = sqrt(n); for (i = 2; i <= k; i++) if (n%i == 0)break; if (i >= k + 1) { printf("%d ", n); m = m + 1; } if (m % 10 == 0) printf("\n"); } printf("\n"); return 0; }
4.“译密码”
#include<stdio.h> int main() { char c; while ((c = getchar()) != '\n') { if ((c >= 'A'&&c <= 'Z') || (c >= 'a'&&c <= 'z')) { c = c + 4; if (c >= 'Z'&&c <= 'Z' + 4 || c > 'z') c = c - 26; } printf("%c", c); } printf("\n"); return 0; }