Pat class B 1009 C language

1009. irony (20)

The time limit

400 ms

Memory limit

65536 kB

Code length limit

8000 B

The procedure of judging questions

Standard

author

CHEN, Yue

Give me an English sentence , Ask you to write a program , Reverse the order of all the words in the sentence .

Input format ： The test input contains a test case , The total length given in one line does not exceed 80 String . A string consists of several words and spaces , The words are made of English letters （ There is a distinction between case and case ） Composed string , Use... Between words 1 Separate the spaces , Type to make sure there are no extra spaces at the end of the sentence .

Output format ： The output of each test case takes up one line , Output the sentences in reverse order .

sample input ：

Hello World Here I Come

sample output ：

Come I Here World Hello

Ideas ： Look for the blank space in the input sentence from the back to the front , Use here strtchr function , This function looks for a character from right to left , Find the pointer that returns the character , No return found NULL. After finding the space, assign the space as ‘\0’, It is equivalent to separating the last word from the previous sentence . Add one more pointer , Point to the first letter of the truncated word , Then output the string starting from the pointer position , That is, the output is the last word .

One 、 Starting variable

1. character string array.

2. A pointer that accepts a space address

Two 、 operation

1. Accept string

2. Look for spaces from the end of the string

3. Find a space and put this position ‘\0’, And add one to the pointer

4. Output the string opened from the pointer position

3、 ... and 、 Code

#include "stdio.h"
#include "string.h"
int main()
{
	char array[81];
	gets(array);//1. Accept string 
	char * p;
	int i;
	for(i = strlen(array) - 1; i >= 0; i--,i = strlen(array) - 1)
	{	

		p = strrchr(array,' ');//2. Look for spaces from the end of the string , If no space is found, return NULL 
		if(!p)
		{
			printf("%s",array);
			break;
		}// If p It's empty , This indicates that the string has been traversed  
		*p = '\0';//3. Find a space and put this position ‘\0’, And add one to the pointer 
		p++;
		printf("%s ",p);//4. Output the string opened from the pointer position 
	}
	return 0;
}

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