サイクルの小さい例、フィポラチのシーケンス、サイクルは1元の2次方程式とswitchの例のプログラムを解きます


# include <stdio.h>

int main(void)
{
	int n;
	int i;
	int f1, f2, f3;

	f1 = 1;
	f2 = 1;

	printf("            :");
	scanf("%d", &n);

	for (i=3; i<n; i++)
	{
		f3 = f1 + f2;
		f1 = f2;
		f2 = f3;
		printf("%d ", f3);
	}

	return 0;
}

 
一元二次方程式の解:
			# include <stdio.h>
			# include <math.h>

			int main(void)
			{	
				double a, b, c;
				double delta;
				double x1, x2;
				char ch;
				
				do {
					printf("              :
"); printf("a = "); scanf("%lf", &a); printf("b = "); scanf("%lf", &b); printf("c = "); scanf("%lf", &c); delta = b*b - 4*a*c; if (delta > 0) { x1 = (-b + sqrt(delta)) / (2*a); x2 = (-b - sqrt(delta)) / (2*a); printf(" ,x1 = %f, x2 = %f
", x1, x2); } else if (0 == delta) { x1 = x2 = (-b) / (2*a); printf(" ,x1 = x2 = %f
", x1, x2); } else { printf(" !"); } printf(" (Y/N):"); scanf(" %c", &ch); //%c , } while ('y'==ch || 'Y'==ch); return 0; }

 
switchの例:
# include <stdio.h>

int main(void)
{
	int val;
	
	printf("          :");
	scanf("%d", &val);
	
	switch (val)
	{
	case 1:
		printf("1  !
"); break; case 2: printf("2 !
"); break; case 3: printf("3 !
"); break; default: printf(" !
"); break; } return 0; }