串

#include<stdio.h>
#include<stdlib.h>
#define MAX 250

typedef struct{
	char data[MAX];
	int length;
} defstring;

//获取字符串长度
int getlen(char str[]){
	int i=0;
	while(str[i])
	i ++;
	return i;
} 

//初始化 
int init_str(defstring *S,char str[]){
	int i=0;
	int len = getlen(str);
	S->length = 0;
	while(i<len && S->length<=MAX){
		S->data[i] = str[i];
		i++;
		S->length ++;
	}
	return 1;
}

//拼接 s1+s2 = T
int str_concat(char s1[],char s2[],defstring *T){
	int len_1 = getlen(s1);
	int len_2 = getlen(s2);
	int i=0;
	T->length = 0;
	//拼接长度小于MAX的情况 
	if(len_1 + len_2 <= MAX){
		while(i<len_1){
			T->data[i] = s1[i];
			T->length ++;
			i++;
		}
		i=0;
		while(i<len_2){
			T->data[T->length] = s2[i];
			T->length++;
			i++;
		}
	}else{			//拼接长度大于MAX的情况(两种) 
		if(len_1 >= MAX){
			for(int j=0;j<MAX;j++){
				T->data[j] = s1[j];
				T->length ++;
			}
		}else{
			i=0;
			while(i<len_1){
			T->data[i] = s1[i];
			T->length ++;
			i++;
			}
			for(int j=0;j<MAX-i;j++){
				T->data[T->length] = s2[j];
				T->length ++;
			}
		}
	}
	return 1;
}

//插入
int ins_str(defstring *S,int address,char ins[]){
	int len_ins = getlen(ins);
	int j = 0;
	int pos = (S->length)-1;
	//判断是否可插入 
	if(address<1 || address>(S->length) || len_ins>(S->length) || len_ins == 0)
		return 0;
	//字符串向后移动 
	for(int i=1;i<=S->length-address;i++){
		S->data[pos+len_ins] = S->data[pos];
		pos --;		
	}
	//字符串插入 
	while(j<len_ins){
		S->data[address+j] = ins[j];
		j++;
		S->length++;
	}
	return 1;
	
}

//删除
int del_str(defstring *D,int address,int len,char del[]){
	//判断是否可删除 
	if(len>(D->length) || len<0 || address<1 || address>(D->length))
		return 0;
	//存储被删除的串 
	for(int i=0;i<len;i++){
		D->data[address-1+i] = del[i]; 
		D->length --;
	} 
	//字符串向前填补 
	for(int i=0;i<((D->length)-address+len+1);i++)
		D->data[address-1+i] = D->data[address+len-1+i];
	return 1;
}

//查找、匹配 
int find_str(defstring *F,char find[],int pos){
	int i=pos-1;
	int j=0;	
	int len_find = getlen(find);
	int len_per = F->length;
	//判断是否可查找 
	if(len_find == 0 || len_find > F->length || pos <1 || pos > F->length)
		return -2;
	//查找成功返回位置，查找失败返回-1 
	while(i<=len_per && j<=len_find){
		if(F->data[i] == find[j]){
			i++;
			j++;
			if(j == len_find)
				return (i-len_find);
		}else{
			i = i-j+1;
			j=0;
		}
	}
	return -1;	
}


//打印输出 
void display(defstring *S){
	 printf("数据为:");
	 for(int i=0;i<S->length;i++){
 		printf("%3c",S->data[i]);
 	}
 	printf("\n");
	printf("长度为:%d\n",S->length);
 	printf("\n");	 
}

int main(){
	defstring S;		//测试初始化 
	
	defstring T;		//测试拼接 
	char s1[MAX];
	char s2[MAX];
	
	defstring I;		//测试插入 
	char ins[MAX];
	
	defstring D;		//测试删除 
	char del[MAX];
		
	defstring F;		//测试匹配 
	char find[MAX]; 
	int pos;
	int index;
	
	char str[MAX];		//公共使用变量 
	int address;
	int len; 
	
	/*
	//初始化测试模块 
	printf("请输入一个字符串:");
	scanf("%s",&str);
	init_str(&S,str);   //初始化 
	
	display(&S); 
	*/
	
	/*
	//拼接测试模块 
	printf("请输入需要拼接的字符串s1:");
	scanf("%s",&s1);
	printf("请输入需要拼接的字符串s2:");
	scanf("%s",&s2);
	str_concat(s1,s2,&T);
	
	display(&T);
	*/
	
	/*
	//插入测试模块
	printf("请输入一个字符串:");
	scanf("%s",&str);
	init_str(&I,str);   //初始化 
 	printf("请输入需要插入的字符串ins:");
 	scanf("%s",&ins);
 	printf("请输入插入位置address:");
 	scanf("%d",&address);
 	ins_str(&I,address,ins);
 	
	display(&I);
	*/
	
	/* 
	//删除测试模块
	printf("请输入一个字符串:");
	scanf("%s",&str);
	init_str(&D,str);   //初始化 
 	printf("请输入删除位置address:");
 	scanf("%d",&address);
 	printf("请输入删除长度len:");
 	scanf("%d",&len);
 	del_str(&D,address,len,del);
	
	display(&D);
	*/
	
	/*
	//查找/匹配测试模块
	printf("请输入一个字符串作为母串:");
	scanf("%s",&str);
	init_str(&F,str);   //初始化 
	printf("请输入要查找的字符串find:");
	scanf("%s",&find);
	printf("请输入查找的起始位置pos:");
	scanf("%d",&pos);
 	index = find_str(&F,find,pos);
	if(index == -2) printf("ERROR!\n");
	else if(index == -1) printf("no this string!\n"); 
	else printf("该子串在第 %d 个位置上\n",index); 
	*/
	
	return 0;	
}