c/c++从字符串读取内容，并且对其排序之后保存到结构体数组里面（学习笔记）

朱雀 2023-02-17 14:50 12阅读 0赞

# 从字符串读取内容，并且对其排序之后保存到结构体数组里面 #

#include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
    
    #define  NUM  4
    
    struct student_t{ 
    	char *name;
    	int age;
    	int score;
    };
     
    // 用字符串内容初始化结构体内存
    void initCls( struct student_t *p, char *s )
    { 
    	int i = 0;
    	char *t = strtok( s, ";," );
    	while( t != NULL ){ 
    		//p[i].name = t;
    		p[i].name = malloc( strlen(t) + 1 );
    		strcpy( p[i].name, t );	
    		
    		t = strtok( NULL, ",;" );
    		p[i].age = atoi( t );
    		t = strtok( NULL, ",;" );
    		p[i].score = atoi( t );
    		t = strtok( NULL, ",;" );
    		i++;
    	}
    }
    
    
    int cmpAge( struct student_t *s1, struct student_t *s2 )
    { 
    	return s1->age - s2->age;
    }
    
    int cmpScore( struct student_t *s1, struct student_t *s2 )
    { 
    	return s1->score - s2->score;
    }
    
    int cmpName( struct student_t *s1, struct student_t *s2 )
    { 
    	return strcmp( s1->name, s2->name );
    }
    
    // 根据三种条件排序
    void sortCls( struct student_t  *p, 
    		int (*fp)( struct student_t *, struct student_t *) )		//这个是回调函数的应用，其中sortCls函数的参数中有函数指针，那么sortCls是回调函数，参数中的函数指针是条件函数，条件函数会在回调函数中出现(如第57行),这是回调函数的典型应用
    { 
    	int i = 0, j = 0;
    	for( i = 0; i < NUM - 1; i++ ){ 
    		for( j = 0; j < NUM - i - 1; j++ ){ 
    		// if( p[j].age > p[j+1].age ){ 
    			//if( p[j].score > p[j+1].score ){ 
    			if( fp( p+j, p+j+1) > 0 ){ 
    				struct student_t tmp = p[j];
    				p[j] = p[j+1];
    				p[j+1] = tmp;
    			}	
    		}
    	}	
    }
    
    
    // *(p+i).name;
    void showCls( struct student_t *p )
    { 
    	// 查看所有信息
    	int i = 0;
    	for( i = 0; i < NUM; i++ ){ 
    		printf("student info::name = %s, age = %d, score = %d\n",
    			(*(p+i)).name, p[i].age, (p+i)->score );
    	}	
    }
    
    	// 结束时释放内存
    void destoryCls( struct student_t *p )
    { 
    	//free( name );
    	int i = 0;
    	for( i = 0; i < NUM; i++ ){ 
    		free( p[i].name );
    		p[i].name = NULL;
    	}
    }
    
    int main()
    { 
    	char data[]= { "zhangsan,20,90;lisi,21,100;wangwu,18,98;jack,22,89;"};
    	printf("data = %p\n", data );
    	struct student_t cls[ NUM ];
    	initCls( cls, data );
    
    	data[ 0 ] = 'A';
    
    // sortCls( cls, cmpAge );
    	sortCls( cls, cmpName );
    // sortCls( cls, cmpScore);
    
    	showCls( cls );
    
    
    	destoryCls( cls );
    }