Removes leading spaces and leading spaces from strings in C.

Removes leading spaces and leading spaces from strings in C.

The string memory diagram is as follows:

Introduce header files:

 1 #include<stdlib.h> 2 #include<stdio.h> 3 #include<string.h>

Function prototype:

1 void trim(char *strIn /*in*/, char *strOut /*in*/);

Implementation Method 1:

void trim(char *strIn, char *strOut){    int i, j ;    i = 0;    j = strlen(strIn) - 1;    while(strIn[i] == ' ')        ++i;    while(strIn[j] == ' ')        --j;    strncpy(strOut, strIn + i , j - i + 1);    strOut[j - i + 1] = '\0';}

Method 2:

1 void trim (char * strIn, char * strOut) {2 3 char * start, * end, * temp; // define the header and tail pointer of the string after spaces are removed and the traversal pointer 4 5 temp = strIn; 6 7 while (* temp = '') {8 ++ temp; 9} 10 11 start = temp; // obtain the header pointer 12 13 temp = strIn + strlen (strIn)-1; // obtain the pointer of the last character of the original string (not '\ 0') 14 15 printf ("% c \ n", * temp ); 16 17 while (* temp = '') {18 -- temp; 19} 20 21 end = temp; // obtain the tail pointer 22 23 24 for (strIn = start; strIn <= end;) {25 * strOut ++ = * strIn ++; 26} 27 28 * strOut = '\ 0'; 29}

Test:

 1 void main(){ 2     char *strIn = "   ak kl  p  "; 3  4     char strOut[100]; 5  6     trim(strIn, strOut); 7  8     printf("*%s*\n",strOut); 9 10     system("pause");11 }