- 实现 mystrcpy(), mystrcmp(), mystrcat(), mystrlen() ;
#include<stdio.h>
void mystrcpy(char *i,char *j) {
while (*j != '\0') {
*i = *j;
i++;
j++;
}
}
int mystrcmp(char *i, char *j) {
if (strlen(i) != strlen(j)) {
return -1;
}
while (*i != '\0') {
if (*i != *j) {
return -1;
}
i++;j++;
}
return 1;
}
void mystrcat(char *i, char *j) {
while (*i != '\0') i++;
while (*j != '\0') {
*i = *j;
i++;
j++;
}
}
int mystrlen(char *i) {
int num = 0;
while (*i != '\0') {
num++;
i++;
}
return num;
}
int main() {
char a[10] = { 0 };
char b[10] = { 0 };
printf("Please input the the string of b:\n");
scanf("%s", b);
mystrcpy(a, b);
printf("strcpy后 a : %s\n", a);
if (mystrcmp(a, b) == 1) {
printf("a,b字符串相等\n");
}
else {
printf("a,b字符串不相等\n");
}
mystrcat(a, b);
printf("strcat后 a : %s\n", a);
printf("%s的长度为%d\n", a, mystrlen(a));
return 0;
}
输入一行字符串(单词和若干空格), 输出该行单词个数。
输出该行单词(每个单词一行)
#include<string>
#include<iostream>
#include<cctype>
using namespace std;
int main() {
string s;
freopen("1.txt", "r", stdin);
getline(cin, s);
int len = s.size(), num = 0;
string ans;
for (int i = 0;i < len;++i) {
if (isalpha(s[i])) {
ans += s[i];
if (!(isalpha(s[i+1]))) {
cout << ans << endl;
num++;
ans.clear();
}
}
}
cout << num << endl;
return 0;
}
- 输入一行字符串,把字符串翻转 。
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main() {
string s;
getline(cin, s);
reverse(begin(s),end(s));
cout << s << endl;
}
- 大整数加法。实现任意范围的两个整数的加法(提示:整数的范围用 int 型的变量无法表示,50位)
#include<iostream>
#include<string>
using namespace std;
struct bign {
int d[1000];
int len;
bign() {
memset(d, 0, sizeof(d));
len = 0;
}
};
bign change(string str) { //将整数转换为bign
bign a;
a.len = str.size();
for (int i = 0;i < a.len;i++) {
a.d[i] = str[a.len - i - 1] - '0';
}
return a;
}
bign add(bign a, bign b) {
bign c;
int carry = 0;
for (int i = 0;i < a.len || i< b.len ;i++) {
int temp = a.d[i] + b.d[i] + carry;
c.d[c.len++] = temp % 10;
carry = temp / 10;
}
if (carry != 0) { //处理进位
c.d[c.len++] = carry;
}
return c;
}
void print(bign a) {
for (int i = a.len - 1;i >= 0;i--) {
printf("%d", a.d[i]);
}
printf("\n");
}
int main() {
printf("输入你要计算的两个大整数\n");
string a, b;
while (cin >> a && cin >> b) {
bign num_a = change(a);
bign num_b = change(b);
bign ans = add(num_a, num_b);
print(ans);
}
return 0;
}