//loop and frequence //
#include<stdio.h>
int main (void)
{
int limit,number,line;
limit=5;
for(line=1;line<=limit; line++)
{
for(number=1; number<=line;number++)
{
printf("%d",number);
}
printf("\n");
}
return 0;
}

1
12
123
1234
12345