#include <stdio.h>
#include <string.h>
void AddSequenceOfNumbersToString(char str[], int start, int end) {
char numstr[16];
int index = 0;
for (int n = start; n < end; n++) {
sprintf(numstr, "%d", n);
sprintf(str + index, "%d", n);
index += strlen(numstr);
}
}
int main() {
char str[32] = "";
AddSequenceOfNumbersToString(str, 7, 14);
puts(str);
return 0;
}
/*
run:
78910111213
*/