1 //strlen - calculate the length of a string//
2
3 #include <stdio.h>
4
5 int strlens(const char *s);
6 char strcats(char *dest, const char *src);
7
8 #define NUM 100
9
10 int main(void)
11 {
12 char c[NUM];
13 char *s;
14 s = c;
15
16 printf("Please input: ");
17 gets(s);
18
19 printf("The length of string is %d.\n",strlens(s));
20 return 0;
21 }
22
23
24 int strlens(const char *s)
25 {
26 int i;
27
28 for (i = 0; *s++ != '\0'; i++);
29
30 return i;
31 }
1 /* concatenate two strings */
2
3 #include <stdio.h>
4
5 char* strcats(char *dest,const char *src);
6
7 int main(void)
8 {
9 char a[100],b[100];
10 char *m,*n;
11 m = a;
12 n = b;
13 printf("Please input: ");
14 gets(m);
15 printf("Please input: ");
16 gets(n);
17
18 puts(m);
19 puts(n);
20 strcats(m,n);
21
22 puts(m) ;
23
24 return 0;
25 }
26
27 char* strcats(char *dest,const char *src)
28 {
29 int i = 0;
30 char *ch = dest;
31
32 while (*ch) {
33 ch++;
34 }
35
36 while (*ch++ = *src++);
37
38 return (dest);
39 }
1 #include <stdio.h>
2
3 char* strcpys(char * dest,const char * src);
4
5 int main(void)
6 {
7 char c[100],d[100], *s,*q;
8 s = c;
9 q = d;
10 printf("Please input: ");
11 gets(s);
12 printf("Please input: ");
13 gets(q);
14
15 strcpys(s,q);
16 puts(s);
17 // puts(q);
18
19 return 0;
20 }
21
22 char* strcpys(char * dest,const char * src)
23 {
24 while (*src != '\0') {
25 *dest++ = *src++;
26 }
27 *dest = '\0';
28
29 return dest;
30
31 }
1 #include <stdio.h>
2
3 strcmps(char *s, char *t);
4
5 int main(void)
6 {
7 int N;
8 char a[100],b[100],*s,*q;
9 s = a;
10 q = b;
11
12 printf("Please input: ");
13 gets(s);
14 printf("Please input: ");
15 gets(q);
16
17 N = strcmps(s,q);
18 printf("%d\n",N);
19
20 return 0;
21 }
22
23 strcmps(char *s, char *t)
24 {
25 while(*s==*t)
26 {
27 if(*s !='\0')
28 return 0;
29 ++s; ++t;
30 }
31 return (*s - *t);
32 }
