// 将数组A中的内容和数组B中的内容进行交换。(数组一样大)
#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <stdlib.h>
int main()
{
int A[10] = { 1,2,3,4,5,6,7,8,9,0 };
int B[10] = { 0,9,8,5,6,12,3,56,5,2 };
int i=0;
//开始交换a,b
for (i = 0; i < sizeof A / sizeof (A[0]); i++)
{
A[i] = A[i] ^ B[i];
B[i] = A[i] ^ B[i];
A[i] = A[i] ^ B[i];
}
for(i = 0; i < sizeof(A) / sizeof(A[0]); i++)
{
printf("%d ", A[i]);
}
printf("\n");
for (i = 0; i < sizeof(A) / sizeof(A[0]); i++)
{
printf("%d ", B[i]);
}
printf("\n");
system("pause");
return 0;
}
//计算1/1-1/2+1/3-…+1/99-1/100的值
#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <stdlib.h>
int main()
{
int sign = 1;
double deno = 2.0, sum = 1.0, term;
while (deno <= 100)
{
sign = -sign;
term = sign / deno;
sum = sum + term;
deno = deno + 1;
}
printf("%7.1f \n", sum);
system("pause");
return 0;
}
//数1到100中出现了多少次9;
//个位:i % 10 = 9; 十位:i / 10 = 9
#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
int i = 0;
int count = 0;
//个位9的个数
for (i = 1; i < 100; i++)
{
if(i % 10 == 9)
count++;
}
//十位9的个数
for (i = 1; i < 100; i++)
{
if(i / 10 == 9)
count++;
}
printf("%d \n", count);
system("pause");
return 0;
}