Question

更具体地说，我想将两个排序的整数列表合并到也进行排序的第三个列表中。我不知道为什么我的代码无法正常工作！这是一些条目和我编写的代码的示例：

文件1：

文件2：

C代码：

#include <stdio.h>
#include <stdlib.h>

void merge(char* arq1, char* arq2){
    FILE* final;
    final = fopen("merge.txt",'w');
    FILE* f1 = fopen(arq1,'rt');
    FILE* f2 = fopen(arq2,'rt');
    if(!f1 || !f2) exit(1);
    // n1 and n2 represents the actual value that's been read. r1 and r2 the status of each file.
    int n1,n2,r1,r2,equal;
    r1 = fscanf(f1,"%d",&n1);
    r2 = fscanf(f2,"%d",&n2);
    while(r1 || r2){
         if((!r1) || (n2 < n1)){
            fprintf(final,"%d ",n2);
            r2 = fscanf(f2,"%d",&n2);
        }else if((!r2) || (n1 < n2)){
            fprintf(final,"%d ",n1);
            r1 = fscanf(f1,"%d",&n1);
        }else{
            equal = n1;
            fprintf(final,"%d ",equal);
            while(n1 == equal) r1 = fscanf(f1,"%d",&n1);
            while(n2 == equal) r2 = fscanf(f2,"%d",&n2);
        }
    }
    fclose(final);
    fclose(f1);
    fclose(f2);
}

int main(int argc, char const *argv[]){
    merge("merge1.txt","merge2.txt"); 

    return 0;
}

该算法的工作原理如下：

尽管至少一个文件仍具有内容，但是其内容将随后保存在merge.txt文件中。如果文件1和2具有相同的内容，我将保存内容并读取2个文件，直到它们找到不同的值，以使合并的文件没有重复的值。

如何将两个已排序的文件合并为一个已排序的文件？

Answer 1

fopen()的模式参数应该是字符串。
fscanf()可以在错误或EOF时返回EOF（-1）
失败时，fscanf()的目标变量的值未定义。

#include <stdio.h>
#include <stdlib.h>

void merge(char* arq1, char* arq2){
    FILE *final;
    final = fopen("merge.txt", "w"); // <<--(1)
    FILE *f1 = fopen(arq1, "rt"); // <<--(1)
    FILE *f2 = fopen(arq2, "rt"); // <<--(1)
    if(!f1 || !f2 || !final) exit(1); // <<--(1)
    // n1 and n2 represents the actual value that's been read. r1 and r2 the status of each file.
    int n1,n2,r1,r2,equal;

    r1 = fscanf(f1, "%d", &n1);
    r2 = fscanf(f2, "%d", &n2);
    while(r1>0 || r2>0){ // <<--(2)
         if(r1 < 1 || n2 < n1){ // <<--(2)
            fprintf(final, "%d ", n2);
            r2 = fscanf(f2, "%d", &n2);
        }else if(r2 < 1 || n1 < n2){ // <<--(2)
            fprintf(final, "%d ", n1);
            r1 = fscanf(f1, "%d", &n1);
        }else{
            equal = n1;
            fprintf(final, "%d ", equal);
            while(n1 == equal && r1 > 0) r1 = fscanf(f1, "%d", &n1); // <<--(2,3)
            while(n2 == equal && r2 > 0) r2 = fscanf(f2, "%d", &n2); // <<--(2,3)
        }
    }
    fclose(final);
    fclose(f1);
    fclose(f2);
}

int main(int argc, char const *argv[]){
    merge("merge1.txt","merge2.txt"); 

    return 0;
}

Answer 2

OP发布的代码无法干净地编译！

这是编译器的输出：

gcc    -ggdb -Wall -Wextra -Wconversion -pedantic -std=gnu11  -c "untitled.c"  

untitled.c: In function ‘merge’:
untitled.c:6:31: warning: passing argument 2 of ‘fopen’ makes pointer from integer without a cast [-Wint-conversion]
     final = fopen("merge.txt",'w');
                               ^~~

In file included from untitled.c:1:0:
/usr/include/stdio.h:232:14: note: expected ‘const char * restrict’ but argument is of type ‘int’
 extern FILE *fopen (const char *__restrict __filename,
              ^~~~~

untitled.c:7:27: warning: multi-character character constant [-Wmultichar]
     FILE* f1 = fopen(arq1,'rt');
                           ^~~~

untitled.c:7:27: warning: passing argument 2 of ‘fopen’ makes pointer from integer without a cast [-Wint-conversion]

In file included from untitled.c:1:0:
/usr/include/stdio.h:232:14: note: expected ‘const char * restrict’ but argument is of type ‘int’
 extern FILE *fopen (const char *__restrict __filename,
              ^~~~~

untitled.c:8:27: warning: multi-character character constant [-Wmultichar]
     FILE* f2 = fopen(arq2,'rt');
                           ^~~~

untitled.c:8:27: warning: passing argument 2 of ‘fopen’ makes pointer from integer without a cast [-Wint-conversion]

In file included from untitled.c:1:0:
/usr/include/stdio.h:232:14: note: expected ‘const char * restrict’ but argument is of type ‘int’
 extern FILE *fopen (const char *__restrict __filename,
              ^~~~~

untitled.c: In function ‘main’:
untitled.c:33:14: warning: unused parameter ‘argc’ [-Wunused-parameter]
 int main(int argc, char const *argv[]){
              ^~~~

untitled.c:33:32: warning: unused parameter ‘argv’ [-Wunused-parameter]
 int main(int argc, char const *argv[]){
                                ^~~~

关于：

final = fopen("merge.txt",'w');

“ mode”参数必须为字符串。建议在“ mode”参数周围使用双引号：

final = fopen("merge.txt","w");

关于：

FILE* f1 = fopen(arq1,'rt');

和以前一样，“ mode”参数必须为字符串。建议：

FILE* f1 = fopen(arq1,"rt");

对于main()函数，由于未使用参数，建议使用签名：

int main( void )

编译时，请始终启用警告，然后修复这些警告

如何将两个排序文件合并为一个排序文件？

2 个答案: