我在编写我们应该编写的函数时遇到了一些问题。据说，这就是它应该如何工作，但它给了我不兼容的指针类型错误，我不知道如何解决它。
问题在于引用 compare_last 函数的 qsort。
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAX_PERSONS 100
//person structure definition goes here
typedef struct{
char last[32];
char first[32];
int year;
}Person;
//function declarations go here
int compare_last(Person * ptr1, Person * ptr2);
void main(void){//main function goes here
char *infilename[20];
char *outfilename[20];
FILE * fptrin;
FILE * fptrout;
int i, j;
Person musicians[MAX_PERSONS];
printf("Enter input file name: ");
scanf("%s", infilename);
printf("Enter output file name: ");
scanf("%s", outfilename);
strcat(*outfilename, ".htm");
fptrin = fopen(*infilename, "r");
fptrout = fopen(*outfilename, "w");
for(i = 0; i < MAX_PERSONS; i++)
{
fscanf(fptrin, "%s %s %i", musicians[i].last, musicians[i].first, &musicians[i].year);
}
qsort(musicians, i, sizeof(musicians[0]), compare_last);
fprintf(fptrout, "<html>\n<body>\n<title>LAB14</title>\n");
for(j = 0; j < i; j++)
{
fprintf(fptrout, "%s %s %i <br>", musicians[j].last, musicians[j].first, musicians[j].year);
}
fprintf(fptrout, "</body>\n</html>\n");
fclose(fptrin);
fclose(fptrout);
}//end main
//function definitions go here
int compare_last(Person * ptr1, Person * ptr2)
{
int result = strcmp(ptr1 -> last, ptr2 -> last);
if(result != 0)
return result;
else
return strcmp(ptr1 -> first, ptr2 -> first);
}
最佳答案
int compare_last(Person * ptr1, Person * ptr2);
应该
int compare_last(void * ptr1, void * ptr2);
然后你需要在
compare_last 中进行转换关于c - 从不兼容的指针类型传递 'qsort' 的参数 4，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/5865570/