Table of Contents

I. Title:

2. Analysis:

III. Code:

     Note:

I. Title:

Reverse the content of a string str and output, the data range: 1<=len(str)<=10000.

Enter description: Enter a string with spaces allowed.

Output description: Output the string in reverse order.

Second, analysis:

(1),

char arr[100] = { 0 };// stop when a space is encounteredscanf("%s", &arr); 

(2),

char arr[100] = { 0 };gets(arr);

The gets() function has only one parameter, and the parameter type is char* type, that is, str can be a character pointer variable name or a character array name.The gets() function is not only more concise than scanf, but also can directly input even if there are spaces in the input string, without having to define multiple character arrays like scanf.Its function is to read a string from the input buffer and store it into the memory space pointed to by the character pointer variable str.

(3),

char arr[100] = { 0 };scanf("%[^\n]", &arr);

Similar to the gets() function, it will not stop when a space is encountered in the question.

Three. Code:h1>

#includeint main(){char arr[100] = { 0 };// 1.//scanf("%s", &arr); //stop when a space is encountered// 2.//scanf("%[^\n]", &arr);// 3.gets(arr);int len ​​= strlen(arr);int left = 0;int right = len - 1;while (left < right){char temp = arr[left];arr[left] = arr[right];arr[right] = temp;left++;right--;} }printf("%s\n", arr);return 0;}

Note:

When using the gets() function, the compiler will automatically take the last newline out of the buffer and discard it, so no newline will be left in the buffer.Therefore, if the gets() function is used before, and the character variable is assigned from the keyboard later, there is no need to absorb the carriage return to clear the buffer, because the carriage return of the buffer has been taken out by gets() and thrown away.But if you used scanf instead of gets() to accept characters, you must use getchar() to clear the buffer before assigning it.