编辑代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
    char *a1 = NULL;
    char *a2 = NULL;
    a1 = (char*)malloc(10*sizeof(char));
    strcpy(a1,"data.bian");//将字符串复制给a1
    a2=(char*)malloc(10*sizeof(char));
    strcpy(a2,"cheng.net");
    int lengthA1 = strlen(a1);
    int lengthA2 = strlen(a2);
    if(!(lengthA1 >lengthA1 +lengthA2))
    {
        a1=(char*)realloc(a1,(lengthA1 + lengthA2+1)*sizeof(char));
    }
    for(int i = lengthA1;i<lengthA1 + lengthA2;i++)
    {
        a1[i] = a2[i-lengthA1];
    }
    a1[lengthA1 +lengthA2] = '\0';
    printf("%s",a1);
    free(a1);
    free(a2);
    return 0;
}