#include <stdio.h>

void cat_data(int *data1, int *data2, int len2);
int main(void){
	
	int data1[7]={1,2};
	int data2[5]={3,4,5,6,7};
	int len2=sizeof(data2)/sizeof(data2[0]);
	cat_data(data1, data2, len2);
	 int *p=data1;
	 for (int i=0;i<7;i++){
	 	printf("data1[%d]=%d\n",i,data1[i]);
	 	p++;
	 }
	 return 0;
}
void cat_data(int *data1, int *data2, int len2)
{
int len1=0;
while (data1[len1] !=0){
len1++;
}
for(int i=0; i<len2; i++ ){
if ((len1 + i) < 7) {
            data1[len1 + i] = data2[i];
}
}
}