删除字符串中的空格

实例

替换前  abc def  ghi

替换后  abcdefghighi

思路

从前往后遍历字符串a，记录空格的个数SpaceNum

a[i] = '' : SpaceNum++

a[i]!='' :  a[i-SpaceNum] = a[i]

参考代码

#include <iostream>
#include <cstring>
using namespace std;

void RemoveSpace(char *a)
{
    if(a == NULL)
        return;
    int len = strlen(a);
    int SpaceNum = 0;
    for(int i = 0; i < len; ++i)
    {
        if(a[i] == ' ')
            ++SpaceNum;
        else if(SpaceNum > 0)
            a[i - SpaceNum] = a[i];
    }
    a[len - SpaceNum] = '';
}

int main()
{
    char a[] = "abc def  ghi";
    cout << a << endl;
    RemoveSpace(a);
    cout << a << endl;
}

结果

abc def ghi
abcdefghi

细节

赋值完后要置结束符''，否则还会记录原来的字符，比如

#include <iostream>
#include <cstring>
using namespace std;

void RemoveSpace(char *a)
{
    if(a == NULL)
        return;
    int len = strlen(a);
    int SpaceNum = 0;
    for(int i = 0; i < len; ++i)
    {
        if(a[i] == ' ')
            ++SpaceNum;
        else if(SpaceNum > 0)
            a[i - SpaceNum] = a[i];
    }
//    a[len - SpaceNum] = '';
}

int main()
{
    char a[] = "abc def  ghi";
    cout << a << endl;
    RemoveSpace(a);
    cout << a << endl;
}

结果

abc def ghi
abcdefghighi