列挙アルゴリズム(一)

#include <stdio.h>

int main(){
	int j,i[5];
	int sign;
	int result;
	int count = 0;
	int num[6];
	float left,right;
	char oper[5] = {' ','+','-','*','/'};
	printf("please input five number:
");
	for (j = 1;j <= 5;j++)
	{
		scanf("%d",&num[j]);
	}
	printf("please input the result you want:
");
	scanf("%d",&result);
	for (i[1]=1;i[1]<=4;i[1]++)
	{
		if (i[1]<4 || num[2]!=0)
		{
			for (i[2]=1;i[2]<=4;i[2]++)
			{
				if (i[2]<4 || num[3]!=0)
				{
					for (i[3]=1;i[3]<=4;i[3]++)
					{
						if (i[3]<4 || num[4]!=0)
						{
							for (i[4]=1;i[4]<=4;i[4]++)
							{
								if (i[4]<4 || num[5]!=0)
								{
									left = 0;
									right = num[1];
									sign = 1;
									for (j=1;j<=4;j++)
									{
										switch(oper[i[j]]){
										case '+' :
											left=left+sign*right;
											sign =1;
											right = num[j+1];
											break;
										case'-':
											left = left+sign*right;
											sign = -1;
											right = num[j+1];
											break;
										case '*':
											right = right * num[j+1];
											break;
										case '/':
											right = right/num[j+1];
											break;

										}
									}
									if (left+sign*right==result)
									{
										count++;
										printf("%5d: ",count);
										for (j=1;j<=4;j++)
										{
											printf("%d%c",num[j],oper[i[j]]);
										}
										printf("%d=%d
",num[5],result);
									}
								}
							}
						}
					}
				}
			}
		}
	}
	if (count==0)
	{
		printf("nothing
");
	}
	return 0;
}