concat

#include<stdio.h>
int main()
{
    char s1[40]="my name is";
    char s2[30]="rony";
    int i=0,len=0,j=0;
    while(s1[i]!='\0')
    {
        i++;
        len++;

    }
    while(s2[j]!='\0')
    {
        s1(len+j)=s2[j];
        j++;
    }
    printf("s1=%s\n",s1);
}