比如“hello world hey baby”
變成“hello world hey baby”
思想是設置兩個指針，前面的(front)一直往前走直到字符串結尾，後面的(last)複製front當前指向的字符，
當遇到多個空格時並不複製，而是等到front指向非空格字符時在往前走。
#include <stdio.h>
#include <stdlib.h>#include <string.h>
void omitSpace(char *str){
char *front = str;
char *last = str;
if(str == NULL) return;
while((*front) == ' ') {++front;} //omit space in the beginning
while((*front) != '\0'){
if((*front) == ' '){
*last = ' ';
while((*front) == ' '){
++front;
}
}else{
*last = *front; //can also add one if condition to avoid unnecessary assignment: if(last != front){*last = *front;}
++front;
}
++last; //front has pointed to the next char, so don't ++front;
}
*last = '\0';
}
int main(){
char *cases[] = {"hello world!!!", " hello world...", " Hello world???", "he llo wor ld ... "};
char **str;
int strIndex = 0;
int letterIndex = 0;
int casesNum = sizeof(cases) / sizeof(char*); //don't forget to be divided by sizeof(char*).
str = (char**)malloc(sizeof(cases));
for(strIndex = 0; strIndex < casesNum; ++strIndex){
str[strIndex] = (char*)malloc(1 + strlen(cases[strIndex]));
for (letterIndex = 0; letterIndex < strlen(cases[strIndex]); ++letterIndex)
{
str[strIndex][letterIndex] = cases[strIndex][letterIndex];
}
str[strIndex][letterIndex] = '\0';
}
for(strIndex = 0; strIndex < casesNum; ++strIndex){
printf("%s\n", str[strIndex]);
omitSpace(str[strIndex]);
printf("%s\n", str[strIndex]);
}
for(strIndex = 0; strIndex < casesNum; ++strIndex){
free(str[strIndex]);
}
free(str);
return 0;
}