C程序设计 （第四版） 谭浩强 习题10.10

习题10.10 从第9题的“职工工资文件”中删除一个职工的数据，再存回原文件。

IDE工具：VS2010

Note: 使用不同的IDE工具可能有部分差异。

 

代码块

方法：使用指针，函数的模块化设计，动态分配内存

说明：文件wage.dat已经存在与项目目录下。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>#define N 3typedef struct{int num;char name[20];char gender;int age;char addr[20];float wage;char health;char edu[10];
}Employee;void initialVar(Employee **emp, int n, char **name){*emp = (Employee*)malloc(n * sizeof(Employee));*name = (char*)malloc(80 * sizeof(char));
}void inputFileName(FILE **file, char *name){printf("Enter File Name: ");scanf("%s", name);*file = fopen(name, "rb");if(*file == NULL){perror("Cannot open this file");system("pause");exit(0);}
}void readFile(FILE **file, Employee *emp, int n){printf("Read File Info:\n");for(int i = 0; i < n; i++){fread(&emp[i].name, sizeof(Employee), 1, *file);fread(&emp[i].wage, sizeof(Employee), 1, *file);printf("Name: %-10s  Wage: %-.2f\n", emp[i].name, emp[i].wage);}printf("\n");fclose(*file);
}void deleteRec(FILE **file, char *name, Employee *emp, int n, int num){for(int i = 0; i < n; i++){if(i == num - 1){for(int j = i; j < n - 1; j++){emp[j] = emp[j+1];}break;}}*file = fopen(name, "wb");if(*file == NULL){perror("Cannot open this file");system("pause");exit(0);}for(int i = 0; i < n - 1; i++){if(fwrite(&emp[i].name, sizeof(Employee), 1, *file) != 1){perror("File Write Error");system("pause");exit(0);}	if(fwrite(&emp[i].wage, sizeof(Employee), 1, *file) != 1){perror("File Write Error");system("pause");exit(0);}}fclose(*file);
}void outputFileNew(FILE **file, char *name, Employee *emp, int n){*file = fopen(name, "rb");if(*file == NULL){perror("Cannot open this file");system("pause");exit(0);}printf("New Employee Info:\n");for(int i = 0; i < n; i++){fread(&emp[i].name, sizeof(Employee), 1, *file);fread(&emp[i].wage, sizeof(Employee), 1, *file);printf("Name: %-10s  Wage: %-.2f\n", emp[i].name, emp[i].wage);}printf("\n");fclose(*file);
}int main(){FILE *file = NULL;Employee *emp = NULL;char *name = NULL;initialVar(&emp, N, &name);inputFileName(&file, name);readFile(&file, emp, N);deleteRec(&file, name, emp, N, 1);outputFileNew(&file, name, emp, N-1);system("pause");return 0;
}

运行结果如下：