//调换两个数组内容
#include <stdio.h>
#include <stdlib.h>
void printArray(int a[], int n) {
int i;
for (i = 0; i < n; i++){
printf("%d ",a[i]);
}
}
int main(){
int a[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
int b[10] = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, };
int i, tmp;
printArray(a, 10);
printArray(b, 10);
for (i = 0; i < 10; i++){
tmp = a[i];
a[i] = b[i];
b[i] = tmp;
}
printArray(a, 10);
printArray(b, 10);
system("pause");
return 0;
}
//计算1/1-1/2+1/3-1/4+1/5 …… + 1/99 - 1/100 的值
#include <stdio.h>
#include <stdlib.h>
int main(){
int i;
double tmp = 1, sum = 0;
for (i = 1; i <= 100; i++){
tmp = 1.0 / i *(i % 2 ? 1 : -1);//变化
sum += tmp;//统计
}
printf("%1f\n",sum);
system("pause");
return 0;
//编写程序数一下 1到 100 的所有整数中出现多少次数字9
#include <stdio.h>
#include <stdlib.h>
int main(){
int i, count = 0;
for (i = 1; i <= 100; i++){
if (i % 10 == 9){
count++;
}
if (i / 10 == 9){
count++;
}
}
printf("共有%d个带9的数\n",count);
system("pause");
return 0;
}