7.3 字符串3 （字符串库函数，用strlen遍历字符数组的正确用法）

Myth丶恋晨 2022-05-19 01:50 12阅读 0赞

![70][]

#include<iostream>
    #include<cstring>
    using namespace std;
    char a[10];
    int main()
    {
    	gets(a);
    	cout << strlen(a) << endl;
    	return 0;
    }

![70 1][] 、'\\0'不计算进去

![70 2][]

![70 3][]

#include<iostream>
    #include<cstring>
    using namespace std;
    void PrintSmall(char s1[], char s2[])//输出字典序小的字符串 
    {
    	if(strcmp(s1, s2) <= 0) 
    		cout << s1;
    	else
    		cout << s2;		
    }
    
    int main()
    {
    	char s1[30];
    	char s2[30];
    	char s3[30];
    	strcpy( s1, "Hello");//s1 = Hello
    	strcpy( s2, s1);//s2 = Hello
    	cout << "1) " << s2 << endl;//1) Hello
    	strcat( s1, ",world");//Hello,world 
    	cout << "2) " << s1 << endl;//2) Hello,world
    	cout << "3) "; PrintSmall("abc", s2); cout << endl;//3) Hello
    	cout << "4) "; PrintSmall("abc", "aaa"); cout << endl;//4) aaa
    	int n = strlen(s2);//5
    	cout << "5) " << n << "," << strlen("abc") << endl;//5) 5,3
    	strupr(s1);//HELLO,WORLD
    	cout << "6) " << s1 << endl;//6) HELLO,WORLD
    	return 0;
    }

![70 4][]

![70 5][]

![70 6][]

![70 7][]

![70 8][]

s\[i\] 为0时终止循环，s\[i\]='\\0'时s\[i\]=0.

[70]: /images/20220519/739aa62b85ca4f56801677d8353dbd97.png
[70 1]: /images/20220519/6a142f39a47547d38293dd929d2ed225.png
[70 2]: /images/20220519/2b30bc41d04e4762bcc2b918ff044c56.png
[70 3]: /images/20220519/582cd612911246be86fe5339959dc70f.png
[70 4]: /images/20220519/861d2aee5a5c41ddaa317acfb3f4133f.png
[70 5]: /images/20220519/6131b261c168416f891e2beae399d408.png
[70 6]: /images/20220519/09e760eab094437a9cc7530fa64d615d.png
[70 7]: /images/20220519/704020bedaca43d89267f27d84495392.png
[70 8]: /images/20220519/d2828a2aaf9946fd96ddfac7afa0d8aa.png