C language Implementation string intercept function left, mid, and right

Iamlaosong

C Language string interception needs their own programming implementation, however, the network era, naturally do not have to write themselves from scratch, the implementation of various methods of online code has been a plethora of, here transcribe a feeling good record.

#include <stdio.h> #include <string.h>/* to intercept n characters from the left of the string */char * Ieft (char *dst,char *src, int n) {    char *p = src;    char *q = DST;    int len = strlen (src);    if (n>len) n = len;    while (n--) * (q++) = * (p++);    * (q++) = ' + '; /* Is it necessary? Very necessary */    return DST;} /* intercept n characters from the middle of a string */char * Mid (char *dst,char *src, int n,int m)/*n for length, m for position */{    char *p = src;    char *q = DST;    int len = strlen (src);    if (n>len) n = len-m;    /* from the first m to the last *    /if (m<0) m=0;    /* from the first start *    /if (M>len) return NULL;    p + = m;    while (n--) * (q++) = * (p++);    * (q++) = ' + '; /* Is it necessary? Very necessary */    return DST;} /* intercept n characters from the right of the string */char * (char *dst,char *src, int n) {    char *p = src;    char *q = DST;    int len = strlen (src);    if (n>len) n = len;    p + = (len-n);   /* Starting from the nth character on the right and ending at 0, it's a coincidence. */While    (* (q++) = * (p++));    return DST;}

C language Implementation string intercept function left, mid, and right