Question

How to count the number of non-overlapping instances of substring in a string in C

Answer 1

#include <stdio.h>
#include <string.h>

int countOccurrences(const char *str, const char *sub) {
    if (sub[0] == '\0') return 0;

    int count = 0;
    const char *tmp = str;
    while ((tmp = strstr(tmp, sub)) != NULL) {
        count++;
        tmp += strlen(sub);
    }

    return count;
}

int main() {
    const char *s = "java php c c++ python php phphp";

    printf("%d\n", countOccurrences(s, "php"));
    
    return 0;
}

 
   
/*
run:
   
3
   
*/

 

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