代码一：
迭代器的v.end()是指容器最后一个元素的后面一个
代码二：
代码三:
点击查看代码
bool is_palindrome(std::string t) {
int i = 0, j, flag = 0;
j = t.size() - 1;
for (; i < j; i++, j--)
{
if (t[i] != t[j]) flag = 1; break;
}
if (flag == 1) return false;
if (flag == 0) return true;}
点击查看代码
std::string dec2n(int x, int n) {
std::string s,s0;
int sum = 0;
while (x) {
s0=x % n+'0';
s=s+s0;
reverse(s.begin(), s.end());
x = x / n;
}
return s;
}
点击查看代码
#include <iostream>
#include<iomanip>
using namespace std;
int main() {
int i,j;
char tou,x,y;
cout << " ";
for (i = 0; i <= 25; i++)
{
x = 'a' + i;
cout << setw(2) << x;
}
cout << endl;
for (i = 1; i <= 25; i++) {
tou = 'A' + i;
cout << setw(2) << i<<setw(2)<<tou;
for (j = 0; j < 25; j++) {
tou = tou + 1;
if (tou == 91) tou = 65;
cout << setw(2) << tou;
}
cout << endl;
}
cout << 26;
for (j = 0; j < 26; j++) {
y = 'A' + j;
cout << setw(2) << y;
}
}
点击查看代码
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <iomanip>
int main() {
srand(time(0));
double correctCount = 0;
int t;
for (int i = 0; i < 10; i++) {
int num1 = rand()%10+1;
int num2 = rand()%10+1;
char op;
switch (rand() % 4) {
case 0: op = '+'; break;
case 1:
if(num2>num1){
t=num2;
num2=num1;
num1=t;
}
op = '-'; break;
case 2: op = '*'; break;
case 3: op = '/'; do { num2 = rand() % 10 + 1; } while (num1 % num2 != 0); break;
}
std::cout << num1 << " " << op << " " << num2 << " = ";
int userAnswer;
std::cin >> userAnswer;
int correctAnswer;
switch (op) {
case '+': correctAnswer = num1 + num2; break;
case '-': correctAnswer = num1 - num2; break;
case '*': correctAnswer = num1 * num2; break;
case '/': correctAnswer = num1 / num2; break;
}
if (userAnswer == correctAnswer) {
correctCount++;
}
}
double accuracy = correctCount / 10 * 100;
std::cout << "正确率：" << accuracy << "%";
return 0;
}