[C++知识库]1.1-C和指针-20220123

原文代码很老式

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>

#define MAX_COLUMN 20
#define MAX_LEN 1000

int Read_Column_Number(int *arr,int max);
void ReArranged(char *output,const char *input,const int *arr,const int count);

int main(){
	int num_column=0;
	int column[MAX_COLUMN]={0};
	char input[MAX_LEN]={0};
	char output[MAX_LEN]={0};
	fputs("Input the column number in pairs:->",stdout);
	num_column=Read_Column_Number(column,MAX_COLUMN);
	fputs("Input the str:->",stdout);
	while(gets(input)!=NULL){
		ReArranged(output,input,column,num_column);
		printf("New->%s\n",output);
		fputs("Input the str:->",stdout);
	}
return 0;}

int Read_Column_Number(int *arr,int max){
	int count=0,ch=0;
	while(1){
		for(int i=0;scanf("%d",&arr[i])==1&&arr[i]>=0&&count<max;count++,i++);
		if(count%2){
			fputs("The number of count must be even,try again!\n",stdout);
			while((ch=getchar())!=EOF&&ch!=10);
		}
		else
			break;
	}
	while((ch=getchar())!=EOF&&ch!=10);
return count;}

void ReArranged(char *output,const char *input,const int *arr,int count){
	for(int i=0,num_char=0,len=strlen(input),len_output=0;i<count;i+=2){
		if(arr[i]>=len||len_output==MAX_LEN-1)
			break;
		num_char=arr[i+1]-arr[i]+1;
		if(len_output+num_char>MAX_LEN-1)
			num_char=MAX_LEN-len_output-1;
		strncpy(output+len_output,input+arr[i],num_char);
		len_output+=num_char;	
	}
}