[已解决]字符串处理函数的问题

lluvio

为什么这里str6出问题但是str4没事呢？

最佳答案

月排行榜 / 总排行榜

巴巴鲁

2020-10-4 11:43:06

str5和str6复制过来后都没有加'\0'，后面会输出乱码

1. char str1[] = "ABCDEFGHIJKLMN";
   
2.     char str2[40];char str3[40];
   
3.     char str4[40];char str5[40];
   
4.     char str6[40];
   
5. 
   
6.     strncpy(str2, str1, sizeof(str2));
   
7.     printf("strlen str2 = %u\n",strlen(str2));
   
8. 
   
9.     strncpy(str3, str2, 5);        str3[5] = '\0';
   
10.     strncpy(str4, str2, 6);
    
11.     printf("strlen str4 = %u\n", strlen(str4));
    
12.     strncpy(str5, str2, 7);        str5[7] = '\0';  //加'\0'
    
13.     strncpy(str6, str2, 4);        str6[4] = '\0'; // 加'\0'
    
14.     printf("strlen str6 = %u\n", strlen(str6));
    
15. 
    
16.     printf("str1 = %s\n", str1);
    
17.     printf("str2 = %s\n", str2);
    
18.     printf("str3 = %s\n", str3);
    
19.     printf("str4 = %s\n", str4);
    
20.     printf("str5 = %s\n", str5);
    
21.     printf("str6 = %s\n", str6);

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lluvio

1. char str1[] = "ABCDEFGHIJKLMN";
   
2.     char str2[40];char str3[40];
   
3.     char str4[40];char str5[40];
   
4.     char str6[40];
   
5. 
   
6.     strncpy(str2, str1, sizeof(str2));
   
7.     printf("strlen str2 = %u\n",strlen(str2));
   
8. 
   
9.     strncpy(str3, str2, 5);        str3[5] = '\0';
   
10.     strncpy(str4, str2, 6);
    
11.     printf("strlen str4 = %u\n", strlen(str4));
    
12.     strncpy(str5, str2, 7);
    
13.     strncpy(str6, str2, 4);        //str6[4] = '\0';
    
14.     printf("strlen str6 = %u\n", strlen(str6));
    
15. 
    
16.     printf("str1 = %s\n", str1);
    
17.     printf("str2 = %s\n", str2);
    
18.     printf("str3 = %s\n", str3);
    
19.     printf("str4 = %s\n", str4);
    
20.     printf("str5 = %s\n", str5);
    
21.     printf("str6 = %s\n", str6);

复制代码

巴巴鲁

str5和str6复制过来后都没有加'\0'，后面会输出乱码

1. char str1[] = "ABCDEFGHIJKLMN";
   
2.     char str2[40];char str3[40];
   
3.     char str4[40];char str5[40];
   
4.     char str6[40];
   
5. 
   
6.     strncpy(str2, str1, sizeof(str2));
   
7.     printf("strlen str2 = %u\n",strlen(str2));
   
8. 
   
9.     strncpy(str3, str2, 5);        str3[5] = '\0';
   
10.     strncpy(str4, str2, 6);
    
11.     printf("strlen str4 = %u\n", strlen(str4));
    
12.     strncpy(str5, str2, 7);        str5[7] = '\0';  //加'\0'
    
13.     strncpy(str6, str2, 4);        str6[4] = '\0'; // 加'\0'
    
14.     printf("strlen str6 = %u\n", strlen(str6));
    
15. 
    
16.     printf("str1 = %s\n", str1);
    
17.     printf("str2 = %s\n", str2);
    
18.     printf("str3 = %s\n", str3);
    
19.     printf("str4 = %s\n", str4);
    
20.     printf("str5 = %s\n", str5);
    
21.     printf("str6 = %s\n", str6);

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当初约定

我用你的源码测试了一下，感觉没问题啊

当初约定

#include<stdio.h>
#include<string.h>
int main()
{
        char str1[] = "ABCDEFGHIJKLMN";
    char str2[40];char str3[40];
    char str4[40];char str5[40];
    char str6[40];

    strncpy(str2, str1, sizeof(str2));
    printf("strlen str2 = %u\n",strlen(str2));

    strncpy(str3, str2, 5);        str3[5] = '\0';
    strncpy(str4, str2, 6);
    printf("strlen str4 = %u\n", strlen(str4));
    strncpy(str5, str2, 7);
    strncpy(str6, str2, 4);        //str6[4] = '\0';
    printf("strlen str6 = %u\n", strlen(str6));

    printf("str1 = %s\n", str1);
    printf("str2 = %s\n", str2);
    printf("str3 = %s\n", str3);
    printf("str4 = %s\n", str4);
    printf("str5 = %s\n", str5);
    printf("str6 = %s\n", str6);
        return 0;
}

巴巴鲁

当初约定 发表于 2020-10-4 11:47
我用你的源码测试了一下，感觉没问题啊

奇怪，是编译器不一样吗？我str5和str6后面都输出乱码