自主实现strcpy，strncpy，strcat，strlen函数的功能

快来打我* 2022-04-06 15:43 250阅读 0赞

\#include<stdio.h>  
\#include <windows.h>  
\#define N 10

void main()  
\{  
char choice = ‘1’;

void mystrcpy(char str_1[],char str_2[]);
    void mystrncpy(char str1[],char str2[]);
    void mystrcat(char str1[],char str2[]);
    void mystrlen(char str1[]);
    
    
    char str1[N];
    char str2[N];
    
    
    
    printf("\n");
    printf("请输入字符串：");
    gets(str1);
    printf("\n");
    printf("请输入字符串：");
    gets(str2);
    printf("\n");
    
    
    printf("1.调用mystrcpy\n");
    printf("2.调用mystrncpy\n");
    printf("3.调用mystrcat\n");
    printf("4.调用mystrlen\n");
    printf("0.Exit the system \n");
    
    printf("Please choise (0-4): \n");
    
    while (choice != '0')

\{  
choice = getchar();

switch(choice)
    {
    	case '1': mystrcpy(str1,str2);break;
        case '2': mystrncpy(str1,str2);break;
    	case '3': mystrcat(str1,str2);break;
    	case '4': mystrlen(str1);break;
    	case '0':exit(0);
    default:
    	printf("Choice Error,Please select again(0-4).");
    
    }

\}  
\}

void mystrcpy(char str\_1\[\],char str\_2\[\])  
\{  
int i;

for(i = 0;i<N;i++)
    {
      str_1[i] = str_2[i];
    }
    str_1[N] = '\0';
    printf("%s",str_1);
    printf("\n");

void mystrncpy(char str1\[\],char str2\[\])  
\{  
int i,n;  
printf(“请输入n，将前n个字符进行复制:”);  
scanf("%d",&n);  
printf("\\n");

for(i = 0;i<n;i++)
    {
      str1[i] = str2[i];
    }
    str1[n] = '\0';
    printf("%s",str1);
    printf("\n");

void mystrcat(char str1\[\],char str2\[\])  
\{

int length = 0,i;//测字符串str1的长度
    for(i = 0;str1[i] != '\0';i++) length++;
    
    for(i = 0;str2[i] != '\0';i++,length++)
    {
    	str1[length] = str2[i];
    }
    str1[length+i] = '\0';
    printf("%s",str1);
    printf("\n");

void mystrlen(char str1\[\])  
\{  
int i,length = 0;

for(i = 0;str1[i] != '\0';i++) length++;
    
    printf("字符串的长度为%d",length);
    printf("\n");