字串操作函數的實現

字串操作函數的實現
字串長度：#include<stdio.h>#include<stdlib.h>#include<assert.h>int my_strlen(const char *s){assert(s);int n=0;while(*s){n++;s++;}return n;}int main(){char s[]="abcedf";printf("%d",my_strlen(s));system("pause");return 0;}字串複製：#include<stdio.h>#include<stdlib.h>#include<assert.h>char *my_strcpy(char *s,const char *c){assert(s);assert(c);char *q=s;while(*s++=*c++){;}return q;}int main(){char s[10]="abced";char c[]="aegdhj";printf("%s",my_strcpy(s,c));system("pause");return 0;}字串比較：#include<stdio.h>#include<stdlib.h>#include<assert.h>int my_strcmp(const char *s,const char *c){assert(s);assert(c);while(*s++==*c++){if(*s){return 0;}}return *s-*c;}int main(){char s[10]="abced";char c[]="aegdhj";if(my_strcmp(s,c))printf("s字串大");else if(my_strcmp==0){printf("字串一樣大");}elseprintf("c字串大");system("pause");return 0;}字串串連：#include<stdio.h>#include<stdlib.h>#include<assert.h>char *my_strcat(char *s,const char *c){assert(s);assert(c);char *q=s;while(*s){s++;}while(*s++=*c++){;}return q;}int main(){char s[20]="abced";char c[]="aegdhj";printf("%s",my_strcat(s,c));system("pause");return 0;}