exc/k&r/04-funcs-and-prog-struct/04-01.c

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2023-07-04 10:28:05 +02:00
#include <stdio.h>
#include <string.h>
#define STRING "test string with lost of stuff"
int strindex(char source[], char searchfor[]);
/* pass optional searchfor arg to strindex with STRING, pretty print result */
int main(int argc, char *argv[])
{
char s[] = STRING;
char *t = (argc > 1) ? argv[1] : "est";
int i = strindex(s, t);
if (i < 0) {
printf("no match\n");
return 1;
}
printf("%s\n", s);
while (i--)
putchar(' ');
printf("^\n");
return 0;
}
/* strindex: return index of the righmost occurence of t in s, -1 if none */
int strindex(char s[], char t[])
{
int i, j;
const int tlen = strlen(t);
j = tlen - 1;
for (i = strlen(s)-1; i; i--)
if (s[i] != t[j])
j = tlen - 1;
else if (!(j--)) // match found
return i;
return -1;
}